title: Closely linked non-additive blood pressure quantitative trait loci.
abstract: There is enough evidence through linkage and substitution mapping to indicate that rat chromosome 1 harbors multiple blood pressure (BP) quantitative trait loci (QTLs). Of these, BP QTL1b was previously reported from our laboratory using congenic strains derived by introgressing normotensive alleles from the LEW rat onto the genetic background of the hypertensive Dahl salt-sensitive (S) rat. The region spanned by QTL1b is quite large (20.92 Mb), thus requiring further mapping with improved resolution so as to facilitate systematic identification of the underlying genetic determinant(s). Using congenic strains containing the LEW rat chromosomal segments on the Dahl salt-sensitive (S) rat background, further iterations of congenic substrains were constructed and characterized. Collective data obtained from this new iteration of congenic substrains provided evidence for further fragmentation of QTL1b with improved resolution. At least two separate genetic determinants of blood pressure underlie QTL1b. These are within 7.40 Mb and 7.31 Mb and are known as the QTL1b1 region and the QTL1b2 region, respectively. A genetic interaction was detected between the two BP QTLs. Interestingly, five of the previously reported differentially expressed genes located within the newly mapped QTL1b1 region remained differentially expressed. The congenic strain S.LEW(D1Mco36-D1Mco101), which harbors the QTL1b1 region alone but not the QTL1b2 region, serves as a genetic tool for further dissection of the QTL1b1 region and validation of Nr2f2 as a positional candidate gene. Overall, this study represents an intermediary yet obligatory progression towards the identification of genetic elements controlling BP.
authors.affiliation: Physiological Genomics Laboratory, Department of Physiology and Pharmacology, University of Toledo College of Medicine, 3035 Arlington Avenue, Toledo, OH 43614, USA.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Toland
authors.forename: Yasser
authors.initials: Y
authors.lastname: Saad
authors.forename: Shane
authors.initials: S
authors.lastname: Yerga-Woolwine
authors.forename: Steven
authors.initials: S
authors.lastname: Ummel
authors.forename: Phyllis
authors.initials: P
authors.lastname: Farms
authors.forename: Ramona
authors.initials: R
authors.lastname: Ramdath
authors.forename: Bryan C
authors.initials: BC
authors.lastname: Frank
authors.forename: Norman H
authors.initials: NH
authors.lastname: Lee
authors.forename: Bina
authors.initials: B
authors.lastname: Joe
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000235:genetics*; D033481:Chromosomes, Mammalian / Q000235:genetics; D018895:Microsatellite Repeats; D040641:Quantitative Trait Loci; D051381:Rats; D020303:Rats, Inbred Dahl; D011917:Rats, Inbred Lew