Localization of a blood pressure QTL to a 2.4-cM interval on rat chromosome 9 using congenic strains.
A blood pressure (BP) quantitative trait locus (QTL) was previously found on rat chromosome 9 using Dahl salt-sensitive (S) and Dahl salt-resistant (R) rats. A congenic strain, S.R(chr9), constructed by introgressing an R chromosomal segment into the S background, previously proved the existence of a BP QTL in a large 34.2-cM segment of chromosome 9. In the current work congenic substrains were constructed from the progenitor congenic strain, S.R(chr9). BP and heart weight comparisons between these congenic substrains and their S control localized the BP QTL to a 4.6-cM interval. Two solute carrier (Na(+)/H(+) exchanger) genes, Nhe2 and Nhe4, were excluded as candidates based on their map locations. A second iteration of congenic substrains was used to localize the QTL further to a 2.4-cM interval. Another solute carrier (Cl(-)/HCO3- exchanger) gene, Ae3, is in this reduced interval and was sequenced for both S and R strains, but no coding sequence variations were found. Ae3 mRNA was not differentially expressed in the kidney of congenic compared to S rats. Although the identity of the QTL remains unknown its map location has been reduced from an interval of 34.2 to 2.4 cM.
Meng
Haijin
H
Department of Physiology and Molecular Medicine, Medical College of Ohio, 3035 Arlington Avenue, Toledo 43614-5804, USA.
Garrett
Michael R
MR
Dene
Howard
H
Rapp
John P
JP
D000818:Animals; D020296:Animals, Congenic; D017920:Antiporters / Q000235:genetics; D001794:Blood Pressure / Q000235:genetics*; D002874:Chromosome Mapping; D018895:Microsatellite Repeats; D020033:Protein Isoforms / Q000235:genetics; D040641:Quantitative Trait Loci; D051381:Rats
D017920:Antiporters; D020033:Protein Isoforms; C489238:Slc4a3 protein, rat