Effect of genetic background on cosegregation of renin alleles and blood pressure in Dahl rats.

The cosegregation of renin alleles and blood pressure was evaluated in segregating populations derived from inbred Dahl salt hypertension sensitive (S) and inbred Dahl salt hypertension resistant (R) rats. The populations were raised on high salt diet (8% NaCl). In F2 and F1 X S populations, there was a significant positive gene-dosage relationship between the S-rat renin allele and blood pressure. In contrast, no such relationship was seen in the F1 X R population. Since in the F1 X R population the genetic background is strongly influenced by genes from the R rat (75% R, 25% S), the result is interpreted to mean that genes at other (unidentified) loci modify the blood pressure effect of the S-rat renin allele.