High-resolution mapping of the blood pressure QTL on chromosome 7 using Dahl rat congenic strains

It was previously shown using Dahl salt-sensitive (S) and salt-resistant (R ) rats that a blood pressure quantitative trait locus (QTL) was present on rat chromosome 7. In the present work, this QTL was localized to a region l ess than 0.54 cM in size on the linkage map using a series of congenic stra ins. This region was contained in a single yeast artificial chromosome that was 220 kb long. This small segment still contained the primary candidate locus Cyp11b1 (11 beta -hydroxylase), but the adjacent candidate genes Cyp1 1b2 (aldosterone synthase) and Cyp11b3 were ruled out. It is concluded that 11 beta -hydroxylase, through its known genetic variants altering the prod uction of 18-hydroxy-11-deoxy corticosterone, is very likely to account for the blood pressure QTL on chromosome 7 in the Dahl rat model of hypertensi on. This QTL accounts for about 23 mm Hg under the condition of 2% NaCl die t for 24 days. (C) 2001 Academic Press.