QTL associated with blood pressure, heart rate, and heart weight in CBA/CaJ and BALB/cJ mice

1 The Jackson Laboratory 2 Howard Hughes Medical Institute, Bar Harbor, Maine 04609 3 Laboratory Animal Resource Research Center, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan To better understand the genetic basis of essential hypertension, we conducted a quantitative trait locus (QTL) analysis of a population of 207 (BALB/cJ x CBA/CaJ) F 2 male mice to identify genomic regions that regulate blood pressure, heart rate, and heart weight. We identified two loci, Bpq6 (blood pressure quantitative locus 6) on chromosome 15 (Chr 15; peak, 16 cM; 95% confidence interval, 0–25 cM) and Bpq7 on Chr 7 (peak, 42 cM; 95% confidence interval, 35–50 cM) that were significantly associated with blood pressure. We also identified two loci, Hrq1 (heart rate quantitative locus 1) and Hrq2 , on D2Mit304 (peak, 72 cM; 95% confidence interval 60–80 cM) and D15Mit184 (peak, 25 cM; 95% confidence interval 20–35 cM), respectively, that were significantly associated with heart rate. A significant gene-gene interaction for heart rate was found between Hrq1 and D1Mit10 (peak, 57 cM; 95% confidence interval, 45–75 cM); the latter QTL was named Hrq3 . We identified a significant locus for heart weight, Hwq1 (heart weight quantitative locus 1), at D14Mit67 (peak, 38 cM; 95% confidence interval, 20–43 cM). Identification of the genes for these QTL should lead to a better understanding of the causes of essential hypertension. quantitative trait loci; hypertension