MAPPING OF A QUANTITATIVE TRAIT LOCUS FOR BLOOD-PRESSURE ON RAT CHROMOSOME-2

A genetic map for rat chromosome 2 that includes five candidate genes for blood pressure regulation was constructed in a region containing a quantitative trait locus (QTL) for blood pressure. Two F-2 population s of male rats raised on high salt (8% NaCl) diet from weaning were st udied: F-2(WKY x S), derived from a cross of Dahl salt-sensitive rats( S) and Wistar-Kyoto rats (WKY); and F-2(MNS X S), derived from a cross of S rats and Milan normotensive strain (hZNS). In both populations a blood pressure QTL was localized between Na+,K+-ATPase alpha 1 isofor m and calmodulin-dependent protein kinase II-delta loci. The LOD score for existence of this blood pressure QTL based on the combined popula tions (n = 330) was 5.66 and accounted for 9.2% of the total variance and 26% of the genetic variance.