SA gene and blood pressure cosegregation using Dahl salt-sensitive rats

Based on the published cDNA base sequence for the (anonymous) SA gene, a polymerase-chain-reaction (PCR) product from the SA gene was obtained from a Dahl salt-sensitive rat kidney cDNA library. Compared to the published sequence, this product had a 102 base pair insert in the 3' end of the cDNA, probably as the result of alternate mRNA splicing. A StuI restriction fragment length polymorphism detected three alleles among various rat strains using this PCR SA gene probe. Alleles at the SA locus strongly cosegregated with blood pressure (P = .0012) in a salt-fed F2 population derived from crossing Dahl S and Lewis rats. In contrast, a cosegregation analysis of blood pressure and SA alleles in salt-fed F2 rats derived from a Dahl S x Wistar-Kyoto cross gave a negative cosegregation result. It is concluded that in certain genetic backgrounds the SA gene (or a closely linked gene) can contribute a significant component of genetic hypertension.