Comprehensive Physiology Wiley Online Library

Chromosomal Substitution Strategies to Localize Genomic Regions Related to Complex Traits

Full Article on Wiley Online Library



Abstract

Chromosomal substitution strategies provide a powerful tool to anonymously reveal the relationship between DNA sequence variants and a normal or disease phenotype of interest. Even in this age of CRISPR‐Cas9 genome engineering, the knockdown or overexpression of a gene provides relevant information to our understanding of complex disease only when a close association of an allelic variant with the phenotype has first been established. Limitations of genetic linkage approaches led to the development of more efficient breeding strategies to substitute chromosomal segments from one animal strain into the genetic background of a different strain, enabling a direct comparison of the phenotypes of the strains with variant(s) that differ only at a defined locus. This substitution can be a whole chromosome (consomic), a part of a chromosome (congenic), or as small as only a single or several alleles (subcongenics). In contrast to complete knockout of a specific candidate gene of interest, which simply studies the effects of complete elimination of the gene, the substitution of naturally occurring variants can provide special insights into the functional actions of wild‐type alleles. Strategies for production of these inbred strains are reviewed, and a number of examples are used to illustrate the utility of these model systems. Consomic/congenic strains provide a number of experimental advantages in the study of functions of genes and their variants, which are emphasized in this article, such as replication of experimental studies; determination of temporal relationships throughout a life; rigorously controlled experiments in which relations between genotype and phenotype can be tested with the confounding effects of heterogeneous genetic backgrounds, both targeted and multilayered; and “omic” studies performed at many levels of functionality, from molecules to organelles, cells to organs, and organs to organismal behavior across the life span. The application of chromosomal substitution strategies and development of consomic/congenic rat and mouse strains have greatly expanded our knowledge of genomic variants and their phenotypic relationship to physiological functions and to complex diseases such as hypertension and cancer. © 2020 American Physiological Society. Compr Physiol 10:365‐388, 2020.

Figure 1. Figure 1. (A) Schematic representation of the derivation of a consomic strain in which parental strains are intercrossed to generate the Fl population (40%–50% heterozygosity; half blue, half red alleles). These rats are then backcrossed with the parental SS strain. The N2 rats that are determined by genotyping to be heterozygous along the target chromosome are then backcrossed for ∼4 to 8 generations [e.g., marker assister selection for rats with most SS (blue) alleles]. This yields offspring with an isogenic SS background for all but the target chromosome as shown in (B). Selected male and female rats are then mated resulting in approximately 25% of the offspring being homozygous for the chromosome of interest. These rats are then inbred to produce a stable inbred consomic strain with the substitution of one entire chromosome from the BN strain into the background of the SS strain. Reprinted, with permission, from Cowley AW, et al., 2004 17.
Figure 2. Figure 2. Example of reduced blood pressure salt sensitivity resulting from substitution of chromosome 13 from the BN into the SS/Mcwi strain (SS‐13BN consomic rat). Shown is the mean arterial pressure (MAP) in conscious SS (n = 18), SS‐13BN (n = 15), and BN (n = 16) rats exposed to a high‐salt (4.0% NaCl) diet for 4 weeks. P < 0.05 comparing SS versus SS; and SS‐13BN versus BN 20.
Figure 3. Figure 3. Example of impact of genomic background on mean arterial pressure (MAP) responses to a high‐salt diet. Substitution of chromosome 18 from the BN to the SS strain (SS‐18BN) greatly reduced salt‐induced hypertension (8.0% diet; 3 weeks). Conversely, substitution of chromosome 18 from SS to the BN strain (BN‐18SS) resulted in a relatively small increase in MAP in response to the high‐salt diet.
Figure 4. Figure 4. Consomic rat panel in which each of the 20 autosomes and the X and Y chromosomes from the BN strain were transferred onto the SS genetic background. Shown are the mean arterial pressure (MAP) in male (A) and female (B) SS, BN, and consomic rat strains (indicated by the substituted chromosome) fed a high‐sodium diet (8.0% NaCl diet; 3 weeks) 89. Consomics with P < 0.05 versus SS of the same sex (*); consomic females differing (P < 0.05) from males are designated by #.
Figure 5. Figure 5. Consomic rat panel in which each of the 20 autosomes and the X and Y chromosomes from the BN strain were transferred onto the fawn‐hooded hypertensive (FHH) genetic background. Comparison of the sensitivity to phenylepinephrine (PE) of the aortic rings of consomic male rats to those of the parental salt‐sensitive rats (SS, black fill) after the rats were fed (A) a low‐salt (LS) diet (0.4% NaCl, A) or (B) a high‐salt (HS) diet (4.0% NaCl; 3 weeks). The numbers within each bar represent the n of that group. Y‐axis, −log EC50. *P < 0.05, significantly different from the SS parental strain; ∝ P < 0.05, significantly different from the same strain on an LS diet 62.
Figure 6. Figure 6. Generation of chromosome Y (chrY) consomic rats. A male individual from the donor strain is first crossed to a female from the host strain. Resulting F1 males are then backcrossed to a female from the host strain to generate the N2 generation. Males from the latter are backcrossed again to females from the host strain, the procedure being repeated (n) times. The genome of the final consomic strain is the same as that of the host strain, with the exception of the MSY from the donor strain. Redrawn, with permission, from Prokop JW and Deschepper CF, 2015 111.
Figure 7. Figure 7. Overview of the consomic xenograph model (CXM) 31. (A) Reduced susceptibility to DMBA‐induced mammary tumors in SS.BN2 consomic rats (n = 14) compared with SS (n = 40), as reported by Adamovic et al. 1. (B) Schematic representation of the SS and SS.BN3 genomes that were modified by TALEN‐mediated editing of the IL2Rγ gene. The number bars represent chromosomes that were derived from SS (white) or BN (black). (C) The transgenically labeled human 231Luc+ breast cancer cells were orthotopically implanted in the MFP (see dashed lines) of SSIL2Rγ and SS.BN3IL2Rγ rats. Tumor progression (e.g., growth, vasculogenesis, and metastasis) was tracked over the duration of the experiment. (D) Since the 231Luc+ tumor cells were the same between strains (gray), any differences in tumor progression can be attributed to differences in the SSIL2Rγ (green) and SS.BN3IL2Rγ (blue) microenvironments 31,33. Reprinted, with permission, from Flister MJ, et al., 2014 31.
Figure 8. Figure 8. Schematic representation of the generation of a congenic strain from congenic strains. (A) With the availability of the consomic SS‐13BN strain, the consomic strain is backcrossed to the homozygous parent strain (SS) to make an F1 generation where the offspring is homozygote for all alleles, except the single heterozygous target chromosome of interest (chr 13 in this case). Brother‐sister mating of the F1 rats results in many recombinations within the target chromosome. (B) Each rat is genotyped, and rats selected for heterozygosity at a particular locus with the goal of selecting a similar recombination in a male and female rat. These rats will be intercrossed yielding homozygosity in about 25% of the offspring, which will then be brother‐sister mated to create the inbred congenic line. To obtain a rat that is homozygous within a single 1‐cM interval, it can be estimated that in a population of 1000 F2 rats, there would be, on average, animals that are congenic at a 10 to 20 cM resolution.
Figure 9. Figure 9. (A) Representation of the overlapping congenic strains developed in which segments of various lengths of chromosome 13 from the Brown‐Norway rat (black bars) were introgressed in the genetic background of the SS rat, by marker‐assisted breeding. Delimitation of the congenic regions is defined by the first outward SS marker allele. Thin bars represent chromosome crossover regions. The table to the right of the graph summarizes the mean arterial pressure (MAP) + SEM on day 14 of high‐salt (HS) diet for each of the congenic strains. Significant differences from the SS strain on day 14 HS (P < 0.05) are also shown. Redrawn, with permission, from Moreno C, et al., 2007 93. (B) Candidate region of chr13 (55.13 BN26) was reduced from 13.4 to 1.37 Mb (position by RN5 genome assembly). The SS regions are indicated in white, while the alleles derived from the Brown‐Norway (BN) rats are indicated in black. The narrowed region (1.37 Mb) is shaded in gray. Mean arterial pressure (MAP) on day 14 of high‐salt (HS) diet for the 13 overlapping strains and the salt‐sensitive (SS) and congenic SS.13BN26 strains is summarized for each of the congenic substrains to the right of the graph. Significant differences from the SS strain on day 14 HS (P < 0.05) are also shown. Redrawn, with permission, from Cowley AW, et al., 2014 18. (C) Representation of a 3.62‐Mb region of chromosome (chr) 13 (26‐N) spanned by six overlapping congenic strains. Various lengths of chr 13 from the Brown‐Norway rat (indicated by black bars) were introgressed into the genetic background of the SS rat (white bar). Mean arterial pressure (MAP) measured on day 14 of high‐NaCl diet is shown in the attached table of each congenic substrain. Significant differences from the SS strain on day 14 HS (P < 0.05) are also shown. The narrowed region (0.71 Mb) is shown within the blue‐boxed area in which reside three candidate genes (AstN1, Pappa2, and MiR488p). Redrawn, with permission, from Cowley AW, et al., 2014 21.
Figure 10. Figure 10. Illustration of the convergence of classic and modern genomic approaches to identify allelic variants associated with hypertension in human and animal model systems. Bidirectional approaches can now be applied to reveal the functional relevance of allelic variants (SNPs) discovered in human populations by GWAS or in rat or mouse models by linkage, congenics, on hybrid diversity panels. Homology mapping using dense genomic sequencing data enables variants discovered in humans to be mapped to mouse and rat where function can be studied in great depth using in vitro and in vivo approaches and validated by gene‐editing techniques. Conversely, variants discovered in animal models can direct searches for homologous variants and studies in human subpopulations containing homologous variants. Reprinted, with permission, from Cowley AW, 2018 16.


Figure 1. (A) Schematic representation of the derivation of a consomic strain in which parental strains are intercrossed to generate the Fl population (40%–50% heterozygosity; half blue, half red alleles). These rats are then backcrossed with the parental SS strain. The N2 rats that are determined by genotyping to be heterozygous along the target chromosome are then backcrossed for ∼4 to 8 generations [e.g., marker assister selection for rats with most SS (blue) alleles]. This yields offspring with an isogenic SS background for all but the target chromosome as shown in (B). Selected male and female rats are then mated resulting in approximately 25% of the offspring being homozygous for the chromosome of interest. These rats are then inbred to produce a stable inbred consomic strain with the substitution of one entire chromosome from the BN strain into the background of the SS strain. Reprinted, with permission, from Cowley AW, et al., 2004 17.


Figure 2. Example of reduced blood pressure salt sensitivity resulting from substitution of chromosome 13 from the BN into the SS/Mcwi strain (SS‐13BN consomic rat). Shown is the mean arterial pressure (MAP) in conscious SS (n = 18), SS‐13BN (n = 15), and BN (n = 16) rats exposed to a high‐salt (4.0% NaCl) diet for 4 weeks. P < 0.05 comparing SS versus SS; and SS‐13BN versus BN 20.


Figure 3. Example of impact of genomic background on mean arterial pressure (MAP) responses to a high‐salt diet. Substitution of chromosome 18 from the BN to the SS strain (SS‐18BN) greatly reduced salt‐induced hypertension (8.0% diet; 3 weeks). Conversely, substitution of chromosome 18 from SS to the BN strain (BN‐18SS) resulted in a relatively small increase in MAP in response to the high‐salt diet.


Figure 4. Consomic rat panel in which each of the 20 autosomes and the X and Y chromosomes from the BN strain were transferred onto the SS genetic background. Shown are the mean arterial pressure (MAP) in male (A) and female (B) SS, BN, and consomic rat strains (indicated by the substituted chromosome) fed a high‐sodium diet (8.0% NaCl diet; 3 weeks) 89. Consomics with P < 0.05 versus SS of the same sex (*); consomic females differing (P < 0.05) from males are designated by #.


Figure 5. Consomic rat panel in which each of the 20 autosomes and the X and Y chromosomes from the BN strain were transferred onto the fawn‐hooded hypertensive (FHH) genetic background. Comparison of the sensitivity to phenylepinephrine (PE) of the aortic rings of consomic male rats to those of the parental salt‐sensitive rats (SS, black fill) after the rats were fed (A) a low‐salt (LS) diet (0.4% NaCl, A) or (B) a high‐salt (HS) diet (4.0% NaCl; 3 weeks). The numbers within each bar represent the n of that group. Y‐axis, −log EC50. *P < 0.05, significantly different from the SS parental strain; ∝ P < 0.05, significantly different from the same strain on an LS diet 62.


Figure 6. Generation of chromosome Y (chrY) consomic rats. A male individual from the donor strain is first crossed to a female from the host strain. Resulting F1 males are then backcrossed to a female from the host strain to generate the N2 generation. Males from the latter are backcrossed again to females from the host strain, the procedure being repeated (n) times. The genome of the final consomic strain is the same as that of the host strain, with the exception of the MSY from the donor strain. Redrawn, with permission, from Prokop JW and Deschepper CF, 2015 111.


Figure 7. Overview of the consomic xenograph model (CXM) 31. (A) Reduced susceptibility to DMBA‐induced mammary tumors in SS.BN2 consomic rats (n = 14) compared with SS (n = 40), as reported by Adamovic et al. 1. (B) Schematic representation of the SS and SS.BN3 genomes that were modified by TALEN‐mediated editing of the IL2Rγ gene. The number bars represent chromosomes that were derived from SS (white) or BN (black). (C) The transgenically labeled human 231Luc+ breast cancer cells were orthotopically implanted in the MFP (see dashed lines) of SSIL2Rγ and SS.BN3IL2Rγ rats. Tumor progression (e.g., growth, vasculogenesis, and metastasis) was tracked over the duration of the experiment. (D) Since the 231Luc+ tumor cells were the same between strains (gray), any differences in tumor progression can be attributed to differences in the SSIL2Rγ (green) and SS.BN3IL2Rγ (blue) microenvironments 31,33. Reprinted, with permission, from Flister MJ, et al., 2014 31.


Figure 8. Schematic representation of the generation of a congenic strain from congenic strains. (A) With the availability of the consomic SS‐13BN strain, the consomic strain is backcrossed to the homozygous parent strain (SS) to make an F1 generation where the offspring is homozygote for all alleles, except the single heterozygous target chromosome of interest (chr 13 in this case). Brother‐sister mating of the F1 rats results in many recombinations within the target chromosome. (B) Each rat is genotyped, and rats selected for heterozygosity at a particular locus with the goal of selecting a similar recombination in a male and female rat. These rats will be intercrossed yielding homozygosity in about 25% of the offspring, which will then be brother‐sister mated to create the inbred congenic line. To obtain a rat that is homozygous within a single 1‐cM interval, it can be estimated that in a population of 1000 F2 rats, there would be, on average, animals that are congenic at a 10 to 20 cM resolution.


Figure 9. (A) Representation of the overlapping congenic strains developed in which segments of various lengths of chromosome 13 from the Brown‐Norway rat (black bars) were introgressed in the genetic background of the SS rat, by marker‐assisted breeding. Delimitation of the congenic regions is defined by the first outward SS marker allele. Thin bars represent chromosome crossover regions. The table to the right of the graph summarizes the mean arterial pressure (MAP) + SEM on day 14 of high‐salt (HS) diet for each of the congenic strains. Significant differences from the SS strain on day 14 HS (P < 0.05) are also shown. Redrawn, with permission, from Moreno C, et al., 2007 93. (B) Candidate region of chr13 (55.13 BN26) was reduced from 13.4 to 1.37 Mb (position by RN5 genome assembly). The SS regions are indicated in white, while the alleles derived from the Brown‐Norway (BN) rats are indicated in black. The narrowed region (1.37 Mb) is shaded in gray. Mean arterial pressure (MAP) on day 14 of high‐salt (HS) diet for the 13 overlapping strains and the salt‐sensitive (SS) and congenic SS.13BN26 strains is summarized for each of the congenic substrains to the right of the graph. Significant differences from the SS strain on day 14 HS (P < 0.05) are also shown. Redrawn, with permission, from Cowley AW, et al., 2014 18. (C) Representation of a 3.62‐Mb region of chromosome (chr) 13 (26‐N) spanned by six overlapping congenic strains. Various lengths of chr 13 from the Brown‐Norway rat (indicated by black bars) were introgressed into the genetic background of the SS rat (white bar). Mean arterial pressure (MAP) measured on day 14 of high‐NaCl diet is shown in the attached table of each congenic substrain. Significant differences from the SS strain on day 14 HS (P < 0.05) are also shown. The narrowed region (0.71 Mb) is shown within the blue‐boxed area in which reside three candidate genes (AstN1, Pappa2, and MiR488p). Redrawn, with permission, from Cowley AW, et al., 2014 21.


Figure 10. Illustration of the convergence of classic and modern genomic approaches to identify allelic variants associated with hypertension in human and animal model systems. Bidirectional approaches can now be applied to reveal the functional relevance of allelic variants (SNPs) discovered in human populations by GWAS or in rat or mouse models by linkage, congenics, on hybrid diversity panels. Homology mapping using dense genomic sequencing data enables variants discovered in humans to be mapped to mouse and rat where function can be studied in great depth using in vitro and in vivo approaches and validated by gene‐editing techniques. Conversely, variants discovered in animal models can direct searches for homologous variants and studies in human subpopulations containing homologous variants. Reprinted, with permission, from Cowley AW, 2018 16.
References
 1.Adamovic T, McAllister D, Rowe JJ, Wang T, Jacob HJ, Sugg SL. Genetic mapping of mammary tumor traits to rat chromosome 10 using a novel panel of consomic rats. Cancer Genet Cytogenet 186: 41‐48, 2008.
 2.Adamovic T, McAllister D, Wang T, Adamovic D, Rowe JJ, Moreno C, Lazar J, Jacob HJ, Sugg SL. Identification of novel carcinogen‐mediated mammary tumor susceptibility loci in the rat using the chromosome substitution technique. Genes Chromosomes Cancer 49: 1035‐1045, 2010.
 3.Aitman TJ, Glazier AM, Wallace CA, Cooper LD, Norsworthy PJ, Wahid FN, Al‐Majali KM, Trembling PM, Mann CJ, Shoulders CC, Graf D, St Lezin E, Kurtz TW, Kren V, Pravenec M, Ibrahimi A, Abumrad NA, Stanton LW, Scott J. Identification of Cd36 (Fat) as an insulin‐resistance gene causing defective fatty acid and glucose metabolism in hypertensive rats. Nat Genet 21: 76‐83, 1999.
 4.Andrews KR, Good JM, Miller MR, Luikart G, Hohenlohe PA. Harnessing the power of RADseq for ecological and evolutionary genomics. Nat Rev Genet 17: 81‐92, 2016.
 5.Aneas I, Rodrigues MV, Pauletti BA, Silva GJ, Carmona R, Cardoso L, Kwitek AE, Jacob HJ, Soler JM, Krieger JE. Congenic strains provide evidence that four mapped loci in chromosomes 2, 4, and 16 influence hypertension in the SHR. Physiol Genomics 37: 52‐57, 2009.
 6.Bellott DW, Hughes JF, Skaletsky H, Brown LG, Pyntikova T, Cho TJ, Koutseva N, Zaghlul S, Graves T, Rock S, Kremitzki C, Fulton RS, Dugan S, Ding Y, Morton D, Khan Z, Lewis L, Buhay C, Wang Q, Watt J, Holder M, Lee S, Nazareth L, Alfoldi J, Rozen S, Muzny DM, Warren WC, Gibbs RA, Wilson RK, Page DC. Mammalian Y chromosomes retain widely expressed dosage‐sensitive regulators. Nature 508: 494‐499, 2014.
 7.Bock C, Tomazou EM, Brinkman AB, Muller F, Simmer F, Gu H, Jager N, Gnirke A, Stunnenberg HG, Meissner A. Quantitative comparison of genome‐wide DNA methylation mapping technologies. Nat Biotechnol 28: 1106‐1114, 2010.
 8.Boegehold MA. Microvascular structure and function in salt‐sensitive hypertension. Microcirculation 9: 225‐241, 2002.
 9.Buchanan TA, Sipos GF, Gadalah S, Yip KP, Marsh DJ, Hsueh W, Bergman RN. Glucose tolerance and insulin action in rats with renovascular hypertension. Hypertension 18: 341‐347, 1991.
 10.Carlson DF, Fahrenkrug SC, Hackett PB. Targeting DNA with fingers and TALENs. Mol Ther Nucleic Acids 1: e3, 2012.
 11.Chandler CH, Chari S, Kowalski A, Choi L, Tack D, DeNieu M, Pitchers W, Sonnenschein A, Marvin L, Hummel K, Marier C, Victory A, Porter C, Mammel A, Holms J, Sivaratnam G, Dworkin I. How well do you know your mutation? Complex effects of genetic background on expressivity, complementation, and ordering of allelic effects. PLoS Genet 13: e1007075, 2017.
 12.Clark D, Pazdernik N. Biotechnology (e‐book) (2nd ed), Elsevier, 2015.
 13.Cortez D, Marin R, Toledo‐Flores D, Froidevaux L, Liechti A, Waters PD, Grutzner F, Kaessmann H. Origins and functional evolution of Y chromosomes across mammals. Nature 508: 488‐493, 2014.
 14.Cosentino F, Bonetti S, Rehorik R, Eto M, Werner‐Felmayer G, Volpe M, Luscher TF. Nitric‐oxide‐mediated relaxations in salt‐induced hypertension: Effect of chronic beta1 ‐selective receptor blockade. J Hypertens 20: 421‐428, 2002.
 15.Cowley AW Jr. Physiological Genomics: The next three years. Physiol Genomics 14: 169‐170, 2003.
 16.Cowley AW Jr. Chrm3 gene and M3 muscarinic receptors contribute to salt‐sensitive hypertension ‐ but now a physiological puzzle. Hypertension 72: 588‐591, 2018.
 17.Cowley AW Jr, Liang M, Roman RJ, Greene AS, Jacob HJ. Consomic rat model systems for physiological genomics. Acta Physiol Scand 181: 585‐592, 2004.
 18.Cowley AW Jr, Moreno C, Jacob HJ, Peterson CB, Stingo FC, Ahn KW, Liu P, Vannucci M, Laud PW, Reddy P, Lazar J, Evans L, Yang C, Kurth T, Liang M. Characterization of biological pathways associated with a 1.37 Mbp genomic region protective of hypertension in Dahl S rats. Physiol Genomics 46: 398‐410, 2014.
 19.Cowley AW Jr, Roman RJ, Jacob HJ. Application of chromosomal substitution techniques in gene‐function discovery. J Physiol 554: 46‐55, 2004.
 20.Cowley AW Jr, Roman RJ, Kaldunski ML, Dumas P, Dickhout JG, Greene AS, Jacob HJ. Brown Norway chromosome 13 confers protection from high salt to consomic Dahl S rat. Hypertension 37: 456‐461, 2001.
 21.Cowley AW Jr, Yang C, Kumar V, Lazar J, Jacob H, Geurts AM, Liu P, Dayton A, Kurth T, Liang M. Pappa2 is linked to salt‐sensitive hypertension in Dahl S rats. Physiol Genomics 48: 62‐72, 2016.
 22.Davidson AO, Schork N, Jaques BC, Kelman AW, Sutcliffe RG, Reid JL, Dominiczak AF. Blood pressure in genetically hypertensive rats. Influence of the Y chromosome. Hypertension 26: 452‐459, 1995.
 23.Decano JL, Pasion KA, Black N, Giordano NJ, Herrera VL, Ruiz‐Opazo N. Sex‐specific genetic determinants for arterial stiffness in Dahl salt‐sensitive hypertensive rats. BMC Genet 17: 19, 2016.
 24.Deng AY, Menard A, Xiao C, Roy J. Sexual dimorphism on hypertension of quantitative trait loci entrapped in Dahl congenic rats. Clin Exp Hypertens 30: 511‐519, 2008.
 25.Deng Y, Rapp JP. Cosegregation of blood pressure with angiotensin converting enzyme and atrial natriuretic peptide receptor genes using Dahl salt‐sensitive rats. Nat Genet 1: 267‐272, 1992.
 26.Dey G, Jaimovich A, Collins SR, Seki A, Meyer T. Systematic discovery of human gene function and principles of modular organization through phylogenetic profiling. Cell Rep 10: 993‐1006, 2015.
 27.Ellis JA, Stebbing M, Harrap SB. Association of the human Y chromosome with high blood pressure in the general population. Hypertension 36: 731‐733, 2000.
 28.Ely DL, Turner ME. Hypertension in the spontaneously hypertensive rat is linked to the Y chromosome. Hypertension 16: 277‐281, 1990.
 29.ENCODE Project Consortium. An integrated encyclopedia of DNA elements in the human genome. Nature 489: 57‐74, 2012.
 30.Feng D, Yang C, Geurts AM, Kurth T, Liang M, Lazar J, Mattson DL, O'Connor PM, Cowley AW Jr. Increased expression of NAD(P)H oxidase subunit p67(phox) in the renal medulla contributes to excess oxidative stress and salt‐sensitive hypertension. Cell Metab 15: 201‐208, 2012.
 31.Flister MJ, Endres BT, Rudemiller N, Sarkis AB, Santarriaga S, Roy I, Lemke A, Geurts AM, Moreno C, Ran S, Tsaih SW, De Pons J, Carlson DF, Tan W, Fahrenkrug SC, Lazarova Z, Lazar J, North PE, LaViolette PS, Dwinell MB, Shull JD, Jacob HJ. CXM: A new tool for mapping breast cancer risk in the tumor microenvironment. Cancer Res 74: 6419‐6429, 2014.
 32.Flister MJ, Prokop JW, Lazar J, Shimoyama M, Dwinell M, Geurts A, International Committee on Standardized Genetic Nomenclature for Mice, Rat Genome, and Nomenclature Committee. 2015 Guidelines for Establishing Genetically Modified Rat Models for Cardiovascular Research. J Cardiovasc Transl Res 8: 269‐277, 2015.
 33.Flister MJ, Tsaih SW, Stoddard A, Plasterer C, Jagtap J, Parchur AK, Sharma G, Prisco AR, Lemke A, Murphy D, Al‐Gizawiy M, Straza M, Ran S, Geurts AM, Dwinell MR, Greene AS, Bergom C, LaViolette PS, Joshi A. Host genetic modifiers of nonproductive angiogenesis inhibit breast cancer. Breast Cancer Res Treat 165: 53‐64, 2017.
 34.Freedman BI, Rich SS, Yu H, Roh BH, Bowden DW. Linkage heterogeneity of end‐stage renal disease on human chromosome 10. Kidney Int 62: 770‐774, 2002.
 35.Ganguli M, Tobian L, Iwai J. Cardiac output and peripheral resistance in strains of rats sensitive and resistant to NaCl hypertension. Hypertension 1: 3‐7, 1979.
 36.Garrett MR, Rapp JP. Defining the blood pressure QTL on chromosome 7 in Dahl rats by a 177‐kb congenic segment containing Cyp11b1. Mamm Genome 14: 268‐273, 2003.
 37.Gauthier‐Rein KM, Rusch NJ. Distinct endothelial impairment in coronary microvessels from hypertensive Dahl rats. Hypertension 31: 328‐334, 1998.
 38.Geurts AM, Mattson DL, Liu P, Cabacungan E, Skelton MM, Kurth TM, Yang C, Endres BT, Klotz J, Liang M, Cowley AW Jr. Maternal diet during gestation and lactation modifies the severity of salt‐induced hypertension and renal injury in Dahl salt‐sensitive rats. Hypertension 65: 447‐455, 2015.
 39.Gibbs RA, Weinstock GM, Metzker ML, Muzny DM, Sodergren EJ, Scherer S, Scott G, Steffen D, Worley KC, Burch PE, Okwuonu G, Hines S, Lewis L, DeRamo C, Delgado O, Dugan‐Rocha S, Miner G, Morgan M, Hawes A, Gill R, Celera, Holt RA, Adams MD, Amanatides PG, Baden‐Tillson H, Barnstead M, Chin S, Evans CA, Ferriera S, Fosler C, Glodek A, Gu Z, Jennings D, Kraft CL, Nguyen T, Pfannkoch CM, Sitter C, Sutton GG, Venter JC, Woodage T, Smith D, Lee HM, Gustafson E, Cahill P, Kana A, Doucette‐Stamm L, Weinstock K, Fechtel K, Weiss RB, Dunn DM, Green ED, Blakesley RW, Bouffard GG, De Jong PJ, Osoegawa K, Zhu B, Marra M, Schein J, Bosdet I, Fjell C, Jones S, Krzywinski M, Mathewson C, Siddiqui A, Wye N, McPherson J, Zhao S, Fraser CM, Shetty J, Shatsman S, Geer K, Chen Y, Abramzon S, Nierman WC, Havlak PH, Chen R, Durbin KJ, Egan A, Ren Y, Song XZ, Li B, Liu Y, Qin X, Cawley S, Worley KC, Cooney AJ, D'Souza LM, Martin K, Wu JQ, Gonzalez‐Garay ML, Jackson AR, Kalafus KJ, McLeod MP, Milosavljevic A, Virk D, Volkov A, Wheeler DA, Zhang Z, Bailey JA, Eichler EE, Tuzun E, Birney E, Mongin E, Ureta‐Vidal A, Woodwark C, Zdobnov E, Bork P, Suyama M, Torrents D, Alexandersson M, Trask BJ, Young JM, Huang H, Wang H, Xing H, Daniels S, Gietzen D, Schmidt J, Stevens K, Vitt U, Wingrove J, Camara F, Mar Albà M, Abril JF, Guigo R, Smit A, Dubchak I, Rubin EM, Couronne O, Poliakov A, Hübner N, Ganten D, Goesele C, Hummel O, Kreitler T, Lee YA, Monti J, Schulz H, Zimdahl H, Himmelbauer H, Lehrach H, Jacob HJ, Bromberg S, Gullings‐Handley J, Jensen‐Seaman MI, Kwitek AE, Lazar J, Pasko D, Tonellato PJ, Twigger S, Ponting CP, Duarte JM, Rice S, Goodstadt L, Beatson SA, Emes RD, Winter EE, Webber C, Brandt P, Nyakatura G, Adetobi M, Chiaromonte F, Elnitski L, Eswara P, Hardison RC, Hou M, Kolbe D, Makova K, Miller W, Nekrutenko A, Riemer C, Schwartz S, Taylor J, Yang S, Zhang Y, Lindpaintner K, Andrews TD, Caccamo M, Clamp M, Clarke L, Curwen V, Durbin R, Eyras E, Searle SM, Cooper GM, Batzoglou S, Brudno M, Sidow A, Stone EA, Venter JC, Payseur BA, Bourque G, López‐Otín C, Puente XS, Chakrabarti K, Chatterji S, Dewey C, Pachter L, Bray N, Yap VB, Caspi A, Tesler G, Pevzner PA, Haussler D, Roskin KM, Baertsch R, Clawson H, Furey TS, Hinrichs AS, Karolchik D, Kent WJ, Rosenbloom KR, Trumbower H, Weirauch M, Cooper DN, Stenson PD, Ma B, Brent M, Arumugam M, Shteynberg D, Copley RR, Taylor MS, Riethman H, Mudunuri U, Peterson J, Guyer M, Felsenfeld A, Old S, Mockrin S, Collins F, Rat Genome Sequencing Project Consortium. Genome sequence of the Brown Norway rat yields insights into mammalian evolution. Nature 428: 493‐521, 2004.
 40.Glazier AM, Nadeau JH, Aitman TJ. Finding genes that underlie complex traits. Science 298: 2345‐2349, 2002.
 41.Goodarzi MO, Lehman DM, Taylor KD, Guo X, Cui J, Quinones MJ, Clee SM, Yandell BS, Blangero J, Hsueh WA, Attie AD, Stern MP, Rotter JI. SORCS1: A novel human type 2 diabetes susceptibility gene suggested by the mouse. Diabetes 56: 1922‐1929, 2007.
 42.Gopalakrishnan K, Morgan EE, Yerga‐Woolwine S, Farms P, Kumarasamy S, Kalinoski A, Liu X, Wu J, Liu L, Joe B. Augmented rififylin is a risk factor linked to aberrant cardiomyocyte function, short‐QT interval and hypertension. Hypertension 57: 764‐771, 2011.
 43.Graves JA. Sex chromosome specialization and degeneration in mammals. Cell 124: 901‐914, 2006.
 44.Gregorova S, Divina P, Storchova R, Trachtulec Z, Fotopulosova V, Svenson KL, Donahue LR, Paigen B, Forejt J. Mouse consomic strains: Exploiting genetic divergence between Mus m. musculus and Mus m. domesticus subspecies. Genome Res 18: 509‐515, 2008.
 45.Havlik RJ, Garrison RJ, Feinleib M, Kannel WB, Castelli WP, McNamara PM. Blood pressure aggregation in families. Am J Epidemiol 110: 304‐312, 1979.
 46.He X, Zhou S, St Armour GE, Mackay TF, Anholt RR. Epistatic partners of neurogenic genes modulate Drosophila olfactory behavior. Genes Brain Behav 15: 280‐290, 2016.
 47.Heilmann E, Bartling K. The vitamin B 12 serum level at various ages. Folia Haematol Int Mag Klin Morphol Blutforsch 104: 569‐574, 1977.
 48.Hermsen R, de Ligt J, Spee W, Blokzijl F, Schafer S, Adami E, Boymans S, Flink S, van Boxtel R, van der Weide RH, Aitman T, Hubner N, Simonis M, Tabakoff B, Guryev V, Cuppen E. Genomic landscape of rat strain and substrain variation. BMC Genomics 16: 357, 2015.
 49.Hoffman MJ, Flister MJ, Nunez L, Xiao B, Greene AS, Jacob HJ, Moreno C. Female‐specific hypertension loci on rat chromosome 13. Hypertension 62: 557‐563, 2013.
 50.Hunt SC, Stephenson SH, Hopkins PN, Williams RR. Predictors of an increased risk of future hypertension in Utah. A screening analysis. Hypertension 17: 969‐976, 1991.
 51.Hurst GD, Werren JH. The role of selfish genetic elements in eukaryotic evolution. Nat Rev Genet 2: 597‐606, 2001.
 52.Jacob HJ, Brown DM, Bunker RK, Daly MJ, Dzau VJ, Goodman A, Koike G, Kren V, Kurtz T, Lernmark A, Levan G, Mao Y‐P, Pettersson A, Pravenec M, Simon JS, Szpirer C, Szpirer J, Trolliet MR, Winer ES, Lander ES. A genetic linkage map of the laboratory rat, Rattus norvegicus. Nat Genet 9: 63‐69, 1995.
 53.Joe B, Garrett MR, Dene H, Rapp JP. Substitution mapping of a blood pressure quantitative trait locus to a 2.73 Mb region on rat chromosome 1. J Hypertens 21: 2077‐2084, 2003.
 54.Joe B, Saad Y, Dhindaw S, Lee NH, Frank BC, Achinike OH, Luu TV, Gopalakrishnan K, Toland EJ, Farms P, Yerga‐Woolwine S, Manickavasagam E, Rapp JP, Garrett MR, Coe D, Apte SS, Rankinen T, Perusse L, Ehret GB, Ganesh SK, Cooper RS, O'Connor A, Rice T, Weder AB, Chakravarti A, Rao DC, Bouchard C. Positional identification of variants of Adamts16 linked to inherited hypertension. Hum Mol Genet 18: 2825‐2838, 2009.
 55.Joehanes R, Zhang X, Huan T, Yao C, Ying SX, Nguyen QT, Demirkale CY, Feolo ML, Sharopova NR, Sturcke A, Schaffer AA, Heard‐Costa N, Chen H, Liu PC, Wang R, Woodhouse KA, Tanriverdi K, Freedman JE, Raghavachari N, Dupuis J, Johnson AD, O'Donnell CJ, Levy D, Munson PJ. Integrated genome‐wide analysis of expression quantitative trait loci aids interpretation of genomic association studies. Genome Biol 18: 16, 2017.
 56.Kobori S, Nomura Y, Miu A, Yokobayashi Y. High‐throughput assay and engineering of self‐cleaving ribozymes by sequencing. Nucleic Acids Res 43: e85, 2015.
 57.Koller DL, Liu L, Alam I, Sun Q, Econs MJ, Foroud T, Turner CH. Linkage screen for BMD phenotypes in male and female COP and DA rat strains. J Bone Miner Res 23: 1382‐1388, 2008.
 58.Kotchen TA, Cowley AW Jr, Liang M. Ushering Hypertension Into a New Era of Precision Medicine. JAMA 315: 343‐344, 2016.
 59.Kotchen TA, Kotchen JM, Grim CE, George V, Kaldunski ML, Cowley AW, Hamet P, Chelius TH. Genetic determinants of hypertension: Identification of candidate phenotypes. Hypertension 36: 7‐13, 2000.
 60.Kotchen TA, Zhang HY, Covelli M, Blehschmidt N. Insulin resistance and blood pressure in Dahl rats and in one‐kidney, one‐clip hypertensive rats. Am J Phys 261: E692‐E697, 1991.
 61.Kumarasamy S, Gopalakrishnan K, Abdul‐Majeed S, Partow‐Navid R, Farms P, Joe B. Construction of two novel reciprocal conplastic rat strains and characterization of cardiac mitochondria. Am J Physiol Heart Circ Physiol 304: H22‐H32, 2013.
 62.Kunert MP, Drenjancevic‐Peric I, Dwinell MR, Lombard JH, Cowley AW Jr, Greene AS, Kwitek AE, Jacob HJ. Consomic strategies to localize genomic regions related to vascular reactivity in the Dahl salt‐sensitive rat. Physiol Genomics 26: 218‐225, 2006.
 63.Kwitek‐Black AE, Jacob HJ. The use of designer rats in the genetic dissection of hypertension. Curr Hypertens Rep 3: 12‐18, 2001.
 64.Lahn BT, Page DC. Functional coherence of the human Y chromosome. Science 278: 675‐680, 1997.
 65.Lahn BT, Page DC. Four evolutionary strata on the human X chromosome. Science 286: 964‐967, 1999.
 66.Laird PW. Principles and challenges of genomewide DNA methylation analysis. Nat Rev Genet 11: 191‐203, 2010.
 67.Lander ES, Botstein D. Mapping Mendelian factors underlying quantitative traits using RFLP linkage maps. Genetics 121: 185‐199, 1989.
 68.Lander ES, Linton LM, Birren B, Nusbaum C, Zody MC, Baldwin J, Devon K, Dewar K, Doyle M, FitzHugh W, Funke R, Gage D, Harris K, Heaford A, Howland J, Kann L, Lehoczky J, LeVine R, McEwan P, McKernan K, Meldrim J, Mesirov JP, Miranda C, Morris W, Naylor J, Raymond C, Rosetti M, Santos R, Sheridan A, Sougnez C, Stange‐Thomann Y, Stojanovic N, Subramanian A, Wyman D, Rogers J, Sulston J, Ainscough R, Beck S, Bentley D, Burton J, Clee C, Carter N, Coulson A, Deadman R, Deloukas P, Dunham A, Dunham I, Durbin R, French L, Grafham D, Gregory S, Hubbard T, Humphray S, Hunt A, Jones M, Lloyd C, McMurray A, Matthews L, Mercer S, Milne S, Mullikin JC, Mungall A, Plumb R, Ross M, Shownkeen R, Sims S, Waterston RH, Wilson RK, Hillier LW, McPherson JD, Marra MA, Mardis ER, Fulton LA, Chinwalla AT, Pepin KH, Gish WR, Chissoe SL, Wendl MC, Delehaunty KD, Miner TL, Delehaunty A, Kramer JB, Cook LL, Fulton RS, Johnson DL, Minx PJ, Clifton SW, Hawkins T, Branscomb E, Predki P, Richardson P, Wenning S, Slezak T, Doggett N, Cheng JF, Olsen A, Lucas S, Elkin C, Uberbacher E, Frazier M, et al. Initial sequencing and analysis of the human genome. Nature 409: 860‐921, 2001.
 69.Lazar J, O'Meara CC, Sarkis AB, Prisco SZ, Xu H, Fox CS, Chen MH, Broeckel U, Arnett DK, Moreno C, Provoost AP, Jacob HJ. SORCS1 contributes to the development of renal disease in rats and humans. Physiol Genomics 45: 720‐728, 2013.
 70.Liang M, Cowley AW Jr, Mattson DL, Kotchen TA, Liu Y. Epigenomics of hypertension. Semin Nephrol 33: 392‐399, 2013.
 71.Liang M, Lee NH, Wang H, Greene AS, Kwitek AE, Kaldunski ML, Luu TV, Frank BC, Bugenhagen S, Jacob HJ, Cowley AW Jr. Molecular networks in Dahl salt‐sensitive hypertension based on transcriptome analysis of a panel of consomic rats. Physiol Genomics 34: 54‐64, 2008.
 72.Liang M, Yuan B, Rute E, Greene AS, Olivier M, Cowley AW Jr. Insights into Dahl salt‐sensitive hypertension revealed by temporal patterns of renal medullary gene expression. Physiol Genomics 12: 229‐237, 2003.
 73.Liang M, Yuan B, Rute E, Greene AS, Zou AP, Soares P, GD MC, Slocum GR, Jacob HJ, Cowley AW Jr. Renal medullary genes in salt‐sensitive hypertension: A chromosomal substitution and cDNA microarray study. Physiol Genomics 8: 139‐149, 2002.
 74.Lim SS, Vos T, Flaxman AD, Danaei G, Shibuya K, Adair‐Rohani H, Amann M, Anderson HR, Andrews KG, Aryee M, Atkinson C, Bacchus LJ, Bahalim AN, Balakrishnan K, Balmes J, Barker‐Collo S, Baxter A, Bell ML, Blore JD, Blyth F, Bonner C, Borges G, Bourne R, Boussinesq M, Brauer M, Brooks P, Bruce NG, Brunekreef B, Bryan‐Hancock C, Bucello C, Buchbinder R, Bull F, Burnett RT, Byers TE, Calabria B, Carapetis J, Carnahan E, Chafe Z, Charlson F, Chen H, Chen JS, Cheng AT, Child JC, Cohen A, Colson KE, Cowie BC, Darby S, Darling S, Davis A, Degenhardt L, Dentener F, Des Jarlais DC, Devries K, Dherani M, Ding EL, Dorsey ER, Driscoll T, Edmond K, Ali SE, Engell RE, Erwin PJ, Fahimi S, Falder G, Farzadfar F, Ferrari A, Finucane MM, Flaxman S, Fowkes FG, Freedman G, Freeman MK, Gakidou E, Ghosh S, Giovannucci E, Gmel G, Graham K, Grainger R, Grant B, Gunnell D, Gutierrez HR, Hall W, Hoek HW, Hogan A, Hosgood HD 3rd, Hoy D, Hu H, Hubbell BJ, Hutchings SJ, Ibeanusi SE, Jacklyn GL, Jasrasaria R, Jonas JB, Kan H, Kanis JA, Kassebaum N, Kawakami N, Khang YH, Khatibzadeh S, Khoo JP, Kok C, Laden F, Lalloo R, Lan Q, Lathlean T, Leasher JL, Leigh J, Li Y, Lin JK, Lipshultz SE, London S, Lozano R, Lu Y, Mak J, Malekzadeh R, Mallinger L, Marcenes W, March L, Marks R, Martin R, McGale P, McGrath J, Mehta S, Mensah GA, Merriman TR, Micha R, Michaud C, Mishra V, Mohd Hanafiah K, Mokdad AA, Morawska L, Mozaffarian D, Murphy T, Naghavi M, Neal B, Nelson PK, Nolla JM, Norman R, Olives C, Omer SB, Orchard J, Osborne R, Ostro B, Page A, Pandey KD, Parry CD, Passmore E, Patra J, Pearce N, Pelizzari PM, Petzold M, Phillips MR, Pope D, Pope CA 3rd, Powles J, Rao M, Razavi H, Rehfuess EA, Rehm JT, Ritz B, Rivara FP, Roberts T, Robinson C, Rodriguez‐Portales JA, Romieu I, Room R, Rosenfeld LC, Roy A, Rushton L, Salomon JA, Sampson U, Sanchez‐Riera L, Sanman E, Sapkota A, Seedat S, Shi P, Shield K, Shivakoti R, Singh GM, Sleet DA, Smith E, Smith KR, Stapelberg NJ, Steenland K, Stöckl H, Stovner LJ, Straif K, Straney L, Thurston GD, Tran JH, Van Dingenen R, van Donkelaar A, Veerman JL, Vijayakumar L, Weintraub R, Weissman MM, White RA, Whiteford H, Wiersma ST, Wilkinson JD, Williams HC, Williams W, Wilson N, Woolf AD, Yip P, Zielinski JM, Lopez AD, Murray CJ, Ezzati M, AlMazroa MA, Memish ZA. A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990‐2010: A systematic analysis for the Global Burden of Disease Study 2010. Lancet 380: 2224‐2260, 2012.
 75.Lin C, Fesi BD, Marquis M, Bosak NP, Lysenko A, Koshnevisan MA, Duke FF, Theodorides ML, Nelson TM, McDaniel AH, Avigdor M, Arayata CJ, Shaw L, Bachmanov AA, Reed DR. Adiposity QTL Adip20 decomposes into at least four loci when dissected using congenic strains. PLoS One 12: e0188972, 2017.
 76.Lin C, Fesi BD, Marquis M, Bosak NP, Theodorides ML, Avigdor M, McDaniel AH, Duke FF, Lysenko A, Khoshnevisan A, Gantick BR, Arayata CJ, Nelson TM, Bachmanov AA, Reed DR. Body composition QTLs identified in intercross populations are reproducible in consomic mouse strains. PLoS One 10: e0141494, 2015.
 77.Lindholm AK, Dyer KA, Firman RC, Fishman L, Forstmeier W, Holman L, Johannesson H, Knief U, Kokko H, Larracuente AM, Manser A, Montchamp‐Moreau C, Petrosyan VG, Pomiankowski A, Presgraves DC, Safronova LD, Sutter A, Unckless RL, Verspoor RL, Wedell N, Wilkinson GS, Price TAR. The ecology and evolutionary dynamics of meiotic drive. Trends Ecol Evol 31: 315‐326, 2016.
 78.Liu Y, Liu P, Yang C, Cowley AW Jr, Liang M. Base‐resolution maps of 5‐methylcytosine and 5‐hydroxymethylcytosine in Dahl S rats: Effect of salt and genomic sequence. Hypertension 63: 827‐838, 2014.
 79.Liu Y, Usa K, Wang F, Liu P, Geurts AM, Li J, Williams AM, Regner KR, Kong Y, Liu H, Nie J, Liang M. MicroRNA‐214‐3p in the kidney contributes to the development of hypertension. J Am Soc Nephrol 29: 2518‐2528, 2018.
 80.Longini IM Jr, Higgins MW, Hinton PC, Moll PP, Keller JB. Environmental and genetic sources of familial aggregation of blood pressure in Tecumseh, Michigan. Am J Epidemiol 120: 131‐144, 1984.
 81.Lu L, Li P, Yang C, Kurth T, Misale M, Skelton M, Moreno C, Roman RJ, Greene AS, Jacob HJ, Lazar J, Liang M, Cowley AW Jr. Dynamic convergence and divergence of renal genomic and biological pathways in protection from Dahl salt‐sensitive hypertension. Physiol Genomics 41: 63‐70, 2010.
 82.Luscher TF, Raij L, Vanhoutte PM. Endothelium‐dependent vascular responses in normotensive and hypertensive Dahl rats. Hypertension 9: 157‐163, 1987.
 83.Ma L, Li A, Zou D, Xu X, Xia L, Yu J, Bajic VB, Zhang Z. LncRNAWiki: Harnessing community knowledge in collaborative curation of human long non‐coding RNAs. Nucleic Acids Res 43: D187‐D192, 2015.
 84.Malek RL, Wang HY, Kwitek AE, Greene AS, Bhagabati N, Borchardt G, Cahill L, Currier T, Frank B, Fu X, Hasinoff M, Howe E, Letwin N, Luu TV, Saeed A, Sajadi H, Salzberg SL, Sultana R, Thiagarajan M, Tsai J, Veratti K, White J, Quackenbush J, Jacob HJ, Lee NH. Physiogenomic resources for rat models of heart, lung and blood disorders. Nat Genet 38: 234‐239, 2006.
 85.Mashimo T, Takizawa A, Voigt B, Yoshimi K, Hiai H, Kuramoto T, Serikawa T. Generation of knockout rats with X‐linked severe combined immunodeficiency (X‐SCID) using zinc‐finger nucleases. PLoS One 5: e8870, 2010.
 86.Matin A, Collin GB, Asada Y, Varnum D, Nadeau JH. Susceptibility to testicular germ‐cell tumours in a 129.MOLF‐Chr 19 chromosome substitution strain. Nat Genet 23: 237‐240, 1999.
 87.Mattson DL, Dwinell MR, Greene AS, Kwitek AE, Roman RJ, Cowley AW Jr, Jacob HJ. Chromosomal mapping of the genetic basis of hypertension and renal disease in FHH rats. Am J Physiol Renal Physiol 293: F1905‐F1914, 2007.
 88.Mattson DL, Dwinell MR, Greene AS, Kwitek AE, Roman RJ, Jacob HJ, Cowley AW Jr. Chromosome substitution reveals the genetic basis of Dahl salt‐sensitive hypertension and renal disease. Am J Physiol Renal Physiol 295: F837‐F842, 2008.
 89.Mo R, Omvik P, Lund‐Johansen P. The Bergen blood pressure study: Offspring of two hypertensive parents have significantly higher blood pressures than offspring of one hypertensive and one normotensive parent. J Hypertens 13: 1614‐1617, 1995.
 90.Monti J, Plehm R, Schulz H, Ganten D, Kreutz R, Hubner N. Interaction between blood pressure quantitative trait loci in rats in which trait variation at chromosome 1 is conditional upon a specific allele at chromosome 10. Hum Mol Genet 12: 435‐439, 2003.
 91.Moreno C, Dumas P, Kaldunski ML, Tonellato PJ, Greene AS, Roman RJ, Cheng Q, Wang Z, Jacob HJ, Cowley AW Jr. Genomic map of cardiovascular phenotypes of hypertension in female Dahl S rats. Physiol Genomics 15: 243‐257, 2003.
 92.Moreno C, Kaldunski ML, Wang T, Roman RJ, Greene AS, Lazar J, Jacob HJ, Cowley AW Jr. Multiple blood pressure loci on rat chromosome 13 attenuate development of hypertension in the Dahl S hypertensive rat. Physiol Genomics 31: 228‐235, 2007.
 93.Nadeau JH, Auwerx J. The virtuous cycle of human genetics and mouse models in drug discovery. Nat Rev Drug Discov 18: 255‐272, 2019.
 94.Nadeau JH, Balling R, Barsh G, Beier D, Brown SD, Bucan M, Camper S, Carlson G, Copeland N, Eppig J, Fletcher C, Frankel WN, Ganten D, Goldowitz D, Goodnow C, Guenet JL, Hicks G, Hrabe de Angelis M, Jackson I, Jacob HJ, Jenkins N, Johnson D, Justice M, Kay S, Kingsley D, Lehrach H, Magnuson T, Meisler M, Poustka A, Rinchik EM, Rossant J, Russell LB, Schimenti J, Shiroishi T, Skarnes WC, Soriano P, Stanford W, Takahashi JS, Wurst W, Zimmer A. International Mouse Mutagenesis C. Sequence interpretation. Functional annotation of mouse genome sequences. Science 291: 1251‐1255, 2001.
 95.Nadeau JH, Singer JB, Matin A, Lander ES. Analysing complex genetic traits with chromosome substitution strains. Nat Genet 24: 221‐225, 2000.
 96.Nie Y, Kumarasamy S, Waghulde H, Cheng X, Mell B, Czernik PJ, Lecka‐Czernik B, Joe B. High‐resolution mapping of a novel rat blood pressure locus on chromosome 9 to a region containing the Spp2 gene and colocalization of a QTL for bone mass. Physiol Genomics 48: 409‐419, 2016.
 97.Nobrega MA, Fleming S, Roman RJ, Shiozawa M, Schlick N, Lazar J, Jacob HJ. Initial characterization of a rat model of diabetic nephropathy. Diabetes 53: 735‐742, 2004.
 98.Ober C, Loisel DA, Gilad Y. Sex‐specific genetic architecture of human disease. Nat Rev Genet 9: 911‐922, 2008.
 99.Oldham PD, Pickering G, Roberts JA, Sowry GS. The nature of essential hypertension. Lancet 1: 1085‐1093, 1960.
 100.Ooshima A, Yamori Y, Okamoto K. Cardiovascular lesions in the selectively‐bred group of spontaneously hypertensive rats with severe hypertension. Jpn Circ J 36: 797‐812, 1972.
 101.Ozsolak F, Milos PM. RNA sequencing: Advances, challenges and opportunities. Nat Rev Genet 12: 87‐98, 2011.
 102.Padmanabhan S, Joe B. Towards precision medicine for hypertension: A review of genomic, epigenomic, and microbiomic effects on blood pressure in experimental rat models and humans. Physiol Rev 97: 1469‐1528, 2017.
 103.Park PJ. ChIP‐seq: Advantages and challenges of a maturing technology. Nat Rev Genet 10: 669‐680, 2009.
 104.Pickering G. Hypertension. Definitions, natural histories and consequences. Am J Med 52: 570‐583, 1972.
 105.Pickering G. Normotension and hypertension: The mysterious viability of the false. Am J Med 65: 561‐563, 1978.
 106.Pickering GW. High blood pressure. Br Med J 1: 1‐3, 1939.
 107.Pickering GW. Relation between genetic and social factors and arterial pressure. Recenti Prog Med 30: 397‐416, 1961.
 108.Pravenec M, Churchill PC, Churchill MC, Viklicky O, Kazdova L, Aitman TJ, Petretto E, Hubner N, Wallace CA, Zimdahl H, Zidek V, Landa V, Dunbar J, Bidani A, Griffin K, Qi N, Maxova M, Kren V, Mlejnek P, Wang J, Kurtz TW. Identification of renal Cd36 as a determinant of blood pressure and risk for hypertension. Nat Genet 40: 952‐954, 2008.
 109.Pravenec M, Landa V, Zidek V, Musilova A, Kren V, Kazdova L, Aitman TJ, Glazier AM, Ibrahimi A, Abumrad NA, Qi N, Wang JM, St Lezin EM, Kurtz TW. Transgenic rescue of defective Cd36 ameliorates insulin resistance in spontaneously hypertensive rats. Nat Genet 27: 156‐158, 2001.
 110.Prokop JW, Deschepper CF. Chromosome Y genetic variants: Impact in animal models and on human disease. Physiol Genomics 47: 525‐537, 2015.
 111.Prokop JW, Tsaih SW, Faber AB, Boehme S, Underwood AC, Troyer S, Playl L, Milsted A, Turner ME, Ely D, Martins AS, Tutaj M, Lazar J, Dwinell MR, Jacob HJ. The phenotypic impact of the male‐specific region of chromosome‐Y in inbred mating: The role of genetic variants and gene duplications in multiple inbred rat strains. Biol Sex Differ 7: 10, 2016.
 112.Quaschning T, d'Uscio LV, Shaw S, Luscher TF. Vasopeptidase inhibition exhibits endothelial protection in salt‐induced hypertension. Hypertension 37: 1108‐1113, 2001.
 113.Rangel‐Filho A, Lazar J, Moreno C, Geurts A, Jacob HJ. Rab38 modulates proteinuria in model of hypertension‐associated renal disease. J Am Soc Nephrol 24: 283‐292, 2013.
 114.Rapp JP. Dahl salt‐susceptible and salt‐resistant rats. A review. Hypertension 4: 753‐763, 1982.
 115.Rapp JP. Use and misuse of control strains for genetically hypertensive rats. Hypertension 10: 7‐10, 1987.
 116.Rapp JP, Dahl LK. Mendelian inheritance of 18‐ and ll beta‐steroid hydroxylase activities in the adrenals of rats genetically susceptible or resistant to hypertension. Endocrinology 90: 1435‐1446, 1972.
 117.Rapp JP, Joe B. Do epistatic modules exist in the genetic control of blood pressure in Dahl rats? A critical perspective. Physiol Genomics 45: 1193‐1195, 2013.
 118.Rapp JP, Wang SM, Dene H. A genetic polymorphism in the renin gene of Dahl rats cosegregates with blood pressure. Science 243: 542‐544, 1989.
 119.Rau CD, Civelek M, Pan C, Lusis AJ. A suite of tools for biologists that improve accessibility and visualization of large systems genetics datasets: Applications to the Hybrid Mouse Diversity Panel. Methods Mol Biol 1488: 153‐188, 2017.
 120.Reaven GM, Twersky J, Ho H, Chang H. Hypertriglyceridemia in Dahl rats: Effect of sodium intake and gender. Horm Metab Res 23: 44‐45, 1991.
 121.Roman RJ. Gene therapy and heme oxygenase coming of age. Hypertension 43: 1173‐1174, 2004.
 122.Roman RJ, Cowley AW Jr, Greene A, Kwitek AE, Tonellato PJ, Jacob HJ. Consomic rats for the identification of genes and pathways underlying cardiovascular disease. Cold Spring Harb Symp Quant Biol 67: 309‐315, 2002.
 123.Sandler L, Hiraizumi Y, Sandler I. Meiotic drive in natural populations of Drosophila melanogaster. I. The cytogenetic basis of segregation‐distortion. Genetics 44: 233‐250, 1959.
 124.Schaffer BS, Leland‐Wavrin KM, Kurz SG, Colletti JA, Seiler NL, Warren CL, Shull JD. Mapping of three genetic determinants of susceptibility to estrogen‐induced mammary cancer within the Emca8 locus on rat chromosome 5. Cancer Prev Res (Phila) 6: 59‐69, 2013.
 125.Seidlerova J, Staessen JA, Bochud M, Nawrot T, Casamassima N, Citterio L, Kuznetsova T, Jin Y, Manunta P, Richart T, Struijker‐Boudier HA, Fagard R, Filipovsky J, Bianchi G. Arterial properties in relation to genetic variations in the adducin subunits in a white population. Am J Hypertens 22: 21‐26, 2009.
 126.Sethumadhavan S, Vasquez‐Vivar J, Migrino RQ, Harmann L, Jacob HJ, Lazar J. Mitochondrial DNA variant for complex I reveals a role in diabetic cardiac remodeling. J Biol Chem 287: 22174‐22182, 2012.
 127.Shimoyama M, Smith JR, Bryda E, Kuramoto T, Saba L, Dwinell M. Rat genome and model resources. ILAR J 58: 42‐58, 2017.
 128.Singer JB, Hill AE, Burrage LC, Olszens KR, Song J, Justice M, O'Brien WE, Conti DV, Witte JS, Lander ES, Nadeau JH. Genetic dissection of complex traits with chromosome substitution strains of mice. Science 304: 445‐448, 2004.
 129.Singh SK, Lupo PJ, Scheurer ME, Saxena A, Kennedy AE, Ibrahimou B, Barbieri MA, Mills KI, McCauley JL, Okcu MF, Dorak MT. A childhood acute lymphoblastic leukemia genome‐wide association study identifies novel sex‐specific risk variants. Medicine (Baltimore) 95: e5300, 2016.
 130.Skaletsky H, Kuroda‐Kawaguchi T, Minx PJ, Cordum HS, Hillier L, Brown LG, Repping S, Pyntikova T, Ali J, Bieri T, Chinwalla A, Delehaunty A, Delehaunty K, Du H, Fewell G, Fulton L, Fulton R, Graves T, Hou SF, Latrielle P, Leonard S, Mardis E, Maupin R, McPherson J, Miner T, Nash W, Nguyen C, Ozersky P, Pepin K, Rock S, Rohlfing T, Scott K, Schultz B, Strong C, Tin‐Wollam A, Yang SP, Waterston RH, Wilson RK, Rozen S, Page DC. The male‐specific region of the human Y chromosome is a mosaic of discrete sequence classes. Nature 423: 825‐837, 2003.
 131.Steen RG, Kwitek‐Black AE, Glenn C, Gullings‐Handley J, Van Etten W, Atkinson OS, Appel D, Twigger S, Muir M, Mull T, Granados M, Kissebah M, Russo K, Crane R, Popp M, Peden M, Matise T, Brown DM, Lu J, Kingsmore S, Tonellato PJ, Rozen S, Slonim D, Young P, Jacob HJ. A high‐density integrated genetic linkage and radiation hybrid map of the laboratory rat. Genome Res 9: AP1‐8, insert, 1999.
 132.Stoll M, Cowley AW Jr, Tonellato PJ, Greene AS, Kaldunski ML, Roman RJ, Dumas P, Schork NJ, Wang Z, Jacob HJ. A genomic‐systems biology map for cardiovascular function. Science 294: 1723‐1726, 2001.
 133.Takada T, Mita A, Maeno A, Sakai T, Shitara H, Kikkawa Y, Moriwaki K, Yonekawa H, Shiroishi T. Mouse inter‐subspecific consomic strains for genetic dissection of quantitative complex traits. Genome Res 18: 500‐508, 2008.
 134.Takenaka T, Forster H, De Micheli A, Epstein M. Impaired myogenic responsiveness of renal microvessels in Dahl salt‐sensitive rats. Circ Res 71: 471‐480, 1992.
 135.Teumer A, Tin A, Sorice R, Gorski M, Yeo NC, Chu AY, Li M, Li Y, Mijatovic V, Ko YA, Taliun D, Luciani A, Chen MH, Yang Q, Foster MC, Olden M, Hiraki LT, Tayo BO, Fuchsberger C, Dieffenbach AK, Shuldiner AR, Smith AV, Zappa AM, Lupo A, Kollerits B, Ponte B, Stengel B, Kramer BK, Paulweber B, Mitchell BD, Hayward C, Helmer C, Meisinger C, Gieger C, Shaffer CM, Muller C, Langenberg C, Ackermann D, Siscovick D, Dcct/Edic, Boerwinkle E, Kronenberg F, Ehret GB, Homuth G, Waeber G, Navis G, Gambaro G, Malerba G, Eiriksdottir G, Li G, Wichmann HE, Grallert H, Wallaschofski H, Volzke H, Brenner H, Kramer H, Mateo Leach I, Rudan I, Hillege HL, Beckmann JS, Lambert JC, Luan J, Zhao JH, Chalmers J, Coresh J, Denny JC, Butterbach K, Launer LJ, Ferrucci L, Kedenko L, Haun M, Metzger M, Woodward M, Hoffman MJ, Nauck M, Waldenberger M, Pruijm M, Bochud M, Rheinberger M, Verweij N, Wareham NJ, Endlich N, Soranzo N, Polasek O, van der Harst P, Pramstaller PP, Vollenweider P, Wild PS, Gansevoort RT, Rettig R, Biffar R, Carroll RJ, Katz R, Loos RJ, Hwang SJ, Coassin S, Bergmann S, Rosas SE, Stracke S, Harris TB, Corre T, Zeller T, Illig T, Aspelund T, Tanaka T, Lendeckel U, Völker U, Gudnason V, Chouraki V, Koenig W, Kutalik Z, O'Connell JR, Parsa A, Heid IM, Paterson AD, de Boer IH, Devuyst O, Lazar J, Endlich K, Susztak K, Tremblay J, Hamet P, Jacob HJ, Böger CA, Fox CS, Pattaro C, Köttgen A. Genome‐wide association studies identify genetic loci associated with albuminuria in diabetes. Diabetes 65: 803‐817, 2016.
 136.Venter JC, Adams MD, Myers EW, Li PW, Mural RJ, Sutton GG, Smith HO, Yandell M, Evans CA, Holt RA, Gocayne JD, Amanatides P, Ballew RM, Huson DH, Wortman JR, Zhang Q, Kodira CD, Zheng XH, Chen L, Skupski M, Subramanian G, Thomas PD, Zhang J, Gabor Miklos GL, Nelson C, Broder S, Clark AG, Nadeau J, McKusick VA, Zinder N, Levine AJ, Roberts RJ, Simon M, Slayman C, Hunkapiller M, Bolanos R, Delcher A, Dew I, Fasulo D, Flanigan M, Florea L, Halpern A, Hannenhalli S, Kravitz S, Levy S, Mobarry C, Reinert K, Remington K, Abu‐Threideh J, Beasley E, Biddick K, Bonazzi V, Brandon R, Cargill M, Chandramouliswaran I, Charlab R, Chaturvedi K, Deng Z, Di Francesco V, Dunn P, Eilbeck K, Evangelista C, Gabrielian AE, Gan W, Ge W, Gong F, Gu Z, Guan P, Heiman TJ, Higgins ME, Ji RR, Ke Z, Ketchum KA, Lai Z, Lei Y, Li Z, Li J, Liang Y, Lin X, Lu F, Merkulov GV, Milshina N, Moore HM, Naik AK, Narayan VA, Neelam B, Nusskern D, Rusch DB, Salzberg S, Shao W, Shue B, Sun J, Wang Z, Wang A, Wang X, Wang J, Wei M, Wides R, Xiao C, Yan C, Yao A, Ye J, Zhan M, Zhang W, Zhang H, Zhao Q, Zheng L, Zhong F, Zhong W, Zhu S, Zhao S, Gilbert D, Baumhueter S, Spier G, Carter C, Cravchik A, Woodage T, Ali F, An H, Awe A, Baldwin D, Baden H, Barnstead M, Barrow I, Beeson K, Busam D, Carver A, Center A, Cheng ML, Curry L, Danaher S, Davenport L, Desilets R, Dietz S, Dodson K, Doup L, Ferriera S, Garg N, Gluecksmann A, Hart B, Haynes J, Haynes C, Heiner C, Hladun S, Hostin D, Houck J, Howland T, Ibegwam C, Johnson J, Kalush F, Kline L, Koduru S, Love A, Mann F, May D, McCawley S, McIntosh T, McMullen I, Moy M, Moy L, Murphy B, Nelson K, Pfannkoch C, Pratts E, Puri V, Qureshi H, Reardon M, Rodriguez R, Rogers YH, Romblad D, Ruhfel B, Scott R, Sitter C, Smallwood M, Stewart E, Strong R, Suh E, Thomas R, Tint NN, Tse S, Vech C, Wang G, Wetter J, Williams S, Williams M, Windsor S, Winn‐Deen E, Wolfe K, Zaveri J, Zaveri K, Abril JF, Guigó R, Campbell MJ, Sjolander KV, Karlak B, Kejariwal A, Mi H, Lazareva B, Hatton T, Narechania A, Diemer K, Muruganujan A, Guo N, Sato S, Bafna V, Istrail S, Lippert R, Schwartz R, Walenz B, Yooseph S, Allen D, Basu A, Baxendale J, Blick L, Caminha M, Carnes‐Stine J, Caulk P, Chiang YH, Coyne M, Dahlke C, Mays A, Dombroski M, Donnelly M, Ely D, Esparham S, Fosler C, Gire H, Glanowski S, Glasser K, Glodek A, Gorokhov M, Graham K, Gropman B, Harris M, Heil J, Henderson S, Hoover J, Jennings D, Jordan C, Jordan J, Kasha J, Kagan L, Kraft C, Levitsky A, Lewis M, Liu X, Lopez J, Ma D, Majoros W, McDaniel J, Murphy S, Newman M, Nguyen T, Nguyen N, Nodell M, Pan S, Peck J, Peterson M, Rowe W, Sanders R, Scott J, Simpson M, Smith T, Sprague A, Stockwell T, Turner R, Venter E, Wang M, Wen M, Wu D, Wu M, Xia A, Zandieh A, Zhu X. The sequence of the human genome. Science 291: 1304‐1351, 2001.
 137.Wang L, Jiao Y, Cao Y, Liu G, Wang Y, Gu W. Limitation of number of strains and persistence of false positive loci in QTL mapping using recombinant inbred strains. PLoS One 9: e102307, 2014.
 138.Weiss LA, Pan L, Abney M, Ober C. The sex‐specific genetic architecture of quantitative traits in humans. Nat Genet 38: 218‐222, 2006.
 139.Whelton PK, Carey RM. The 2017 Clinical Practice Guideline for high blood pressure. JAMA 318: 2073‐2074, 2017.
 140.Willcox BJ, He Q, Chen R, Yano K, Masaki KH, Grove JS, Donlon TA, Willcox DC, Curb JD. Midlife risk factors and healthy survival in men. JAMA 296: 2343‐2350, 2006.
 141.Yamori Y, Ooshima A, Okamoto K. Genetic factors involved in spontaneous hypertension in rats an analysis of F 2 segregate generation. Jpn Circ J 36: 561‐568, 1972.
 142.Yeo NC, O'Meara CC, Bonomo JA, Veth KN, Tomar R, Flister MJ, Drummond IA, Bowden DW, Freedman BI, Lazar J, Link BA, Jacob HJ. Shroom3 contributes to the maintenance of the glomerular filtration barrier integrity. Genome Res 25: 57‐65, 2015.
 143.Zhang HY, Reddy SR, Kotchen TA. Antihypertensive effect of pioglitazone is not invariably associated with increased insulin sensitivity. Hypertension 24: 106‐110, 1994.
 144.Zhang QY, Dene H, Deng AY, Garrett MR, Jacob HJ, Rapp JP. Interval mapping and congenic strains for a blood pressure QTL on rat chromosome 13. Mamm Genome 8: 636‐641, 1997.
 145.Zhou MS, Kosaka H, Yoneyama H. Potassium augments vascular relaxation mediated by nitric oxide in the carotid arteries of hypertensive Dahl rats. Am J Hypertens 13: 666‐672, 2000.

Teaching Material

Allen W. Cowley Jr. and Melinda R. Dwinell. Chromosomal Substitution Strategies to Localize Genomic Regions Related to Complex Traits. Compr Physiol 10 : 2020, 365-388.

Didactic Synopsis

Major teaching points

• Complex physiological traits are influenced not only by genomic variation, but also environmental and lifestyle factors. The combination of these factors contributes to disease risk, onset and progression.

• Genetic linkage studies have been successfully used to identify quantitative trait loci (QTL) for many complex traits across the genome. In some cases, these QTL map to different chromosomal regions in males and females.

• Consomic rat panels are generated through a breeding strategy to substitute a chromosome from one inbred strain into the genetic background of a different inbred strain. Phenotypic differences between these strains are a consequence of the substituted alleles.

• Further breeding can be used to narrow the region introgressed from a full chromosome to a narrow region of a chromosome to produce a "congenic strain". Congenic strains contain fewer genes within the narrowed chromosomal regions, therefore reducing the number of candidate genes and genetic variants influencing a trait.

• Advances in gene editing techniques provide opportunities to study the function of candidate genes in physiological processes.

Didactic Legends

The following legends to the figures that appear throughout the article are written to be useful for teaching.

Figure 1. Teaching points. The development of a consomic strain through a well defined breeding strategy provides a model to map biology onto the genome. In the case of a consomic strain, one chromosome from a parental strain is introgressed onto the background of a different parental strain. The result is a stable inbred consomic strain with the substitution of a single chromosome from one inbred strain into the background of a second inbred strain.

Figure 2. Teaching points. The utility of a consomic strains can be seen through this example in which chromosome 13 from the normotensive Brown Norway (BN) strain was substituted into the Dahl Salt-Sensitive strain. The introgression of chromosome 13 from the BN significantly reduced the blood pressure in response to a high salt challenge. A region or regions on chromosome 13 are contributing to the salt-sensitivity.

Figure 3. Teaching points. Comparison of the impact of background strain can also be studied using consomic strains. In this example, chromosome 18 was introgressed first from the BN strain into the SS background and subsequently from the SS strain into the BN background. Substitution from the BN to the SS strain resulted in an attenuated blood pressure response to a high salt challenge. The reverse, substitution from the SS to the BN, had only a small effect on the salt-sensitivity.

Figure 4. Teaching points. An even broader and more valuable approach to studying the impact of a chromosomal substitution on a complex trait is through the use of an entire consomic panel. The development of a consomic strain for each autosome and the X and Y chromosomes allows for the detection of multiple chromosomes containing regions with candidate genes involved in a phenotype or disease mechanism. In addition, differences between male and female rats for the same trait are easily identified.

Figure 5. Teaching points. In some cases, having consomic strains developed with the same chromosome (e.g chromosome 13 from the BN strain) introgressed into the background of two different inbred strains (e.g. Salt-sensitive or the Fawn Hooded Hypertensive) refines the chromosomes containing key regions involved in the trait. In other cases, the effect of a different background strain (Salt-sensitive or Fawn Hooded Hypertensive) with substitution from the same inbred strain (BN) points to the interaction of multiple genes involved in the trait.

Figure 6. Teaching points. The importance of the sex chromosomes specific phenotypic diversity. The development of a MSY consomic strain through careful breeding identified key sex-specific differences between the two parental strains. This approach has been used to identify genomic differences between male and female rats and translated to human.

Figure 7. Teaching points. Another fascinating extension of the consomic approach to study complex disease was accomplished through genomic modification of the IL2Rγ gene on a consomic strain. This model can be used to implant human cancer cells and study tumor progression in different microenvironments.

Figure 8. Teaching points. One approach used successfully by many groups to narrow a genomic region mapped to a trait has been to develop congenic strains. Congenic strains contain a small region of the introgressed chromosome, thus narrowing the list of potential genes of interest involved in the development of the phenotype. Through careful breeding, regions can be narrowed to within a 1 cM interval.

Figure 9. Teaching points. The development of overlapping congenic strains covering segments across a chromosome allows for the identification of one or several genomic regions mapping to a trait. These small congenic regions sometimes contain only a handful of genes, making the identification of key genes involved in a disease mechanism manageable. Congenic strains, like consomic strains, are inbred strains and provide a renewable resource for repeated studies and experimental groups.

 

Figure 10. Teaching points. Over the years, different approaches have been used to identify allelic variants associated with a complex disease such as hypertension. The approaches include human population studies, linkage analysis, and a variety of animal models. Approaches using human data to inform animal model studies and variants identified in animal models and subsequently identified in human populations have led to better understanding of the disease mechanism and to treatment approaches. 


Related Articles:

Teaching Material

Contact Editor

Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite

Allen W. Cowley, Melinda R. Dwinell. Chromosomal Substitution Strategies to Localize Genomic Regions Related to Complex Traits. Compr Physiol 2020, 10: 365-388. doi: 10.1002/cphy.c180029