Identification of blood pressure quantitative trait loci that differentiate two hypertensive strains

Objective To describe genetic loci that differentiate blood pressures in two genetically hypertensive strains, the Dahl salt-sensitive (S) rat and the Albino Surgery (AS) rat. Methods A genome scan was performed using 222 genetic markers on an F2 population derived from two hypertensive strains, S and AS. The F2 rats were fed 8% NaCl for 5 weeks before blood pressure measurements were taken. Results Three blood pressure quantitative trait loci (QTL) were detected, one on each of rat chromosomes (RNO) 2, 4 and 8. The QTL on RNO, unlike those on RNO2 and RNO8, was not detected in any of the previous seven linkage analyses reported with the S rat as one of the parental strains. Interactions between genetic loci throughout the genome were sought and interactions involving RNO4 with RNO8 and RNO4 with RNO14 were found. Including the new RNO4 locus identified in the present study, 16 distinct regions of the S rat genome have been demonstrated, by linkage analyses, to harbour loci that control blood pressure in the S rat. Conclusions Increased blood pressure in two hypertensive strains, S and AS, is differentially regulated by genetic factors present on RNOs 2,4 and 8. Therefore, of the 16 distinct genomic regions known to harbour blood pressure QTL in S rats, 13 are likely to contain blood pressure alleles that function similarly in the S rat and the AS rat, whereas three regions differentiate the two strains. (C) 2002 Lippincott Williams Wilkins.