Substrain comparison of genetically hypertensive rats using DNA fingerprinting, and genetic analysis of blood pressure in the inbred rats.

Using DNA fingerprinting, genetic heterogeneity or homogeneity was studied between substrains of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats maintained in Japan. Using human myoglobin minisatellite 33.15 as a probe, we did not detect any inter- or intra-substrain genetic heterogeneities in HinfI digests of SHR or WKY rat DNA. However, analysis of Sau3AI digests of rat DNA using mouse C-6 gene as a probe revealed intra-substrain heterogeneity of 1-2 DNA bands in one of the WKY rat substrains. In the other substrains of SHR and WKY rats, there existed no intra-substrain heterogeneities, but several inter-substrain heterogeneities were observed in both SHR and WKY rats. In another experiment using the inbred substrains of SHR and WKY rats which have been confirmed as genetically homogeneous, we produced F1 and F2 rats, and biometrically analyzed their systolic blood pressure. The results suggested that there may be 1-4 dominant antihypertensinogenic genes with high heritability of 0.6-0.7.