MAPPING OF QUANTITATIVE TRAIT LOCI FOR BLOOD-PRESSURE AND CARDIAC MASS IN THE RAT BY GENOME SCANNING OF RECOMBINANT INBRED STRAINS

In the HXB and BXH recombinant inbred strains derived from the spontan eously hypertensive rat and the normotensive Brown Norway rat, we dete rmined the strain distribution patterns of 500 genetic markers to scan the rodent genome for quantitative trait loci regulating cardiac mass and blood pressure, The markers spanned similar to 1,139 cM of the ge nome and were tested for correlations with left ventricular mass adjus ted for body weight, and with systolic, diastolic, and mean arterial p ressures. The marker for the dopamine 1A receptor (Drd1a) on chromosom e 17 showed the strongest correlation with left ventricular heart weig ht (P = .00038, r = -0.59) and the relationship to heart weight was in dependent of blood pressure. The markers showing the strongest correla tions with systolic, diastolic, and mean arterial pressure were D19Mit 7 on chromosome 19 (P = .0012, r = .55), D2N35 on chromosome 2 (P = .0 008, r = .56), and Il6 on chromosome 4 (P = .0018, r = .53), respectiv ely, These studies demonstrate that the HXB and BXH strains can be eff ectively used for genome scanning studies of complex traits and have r evealed several chromosome regions that may be involved in the genetic control of blood pressure and cardiac mass in the rat.