Wild rats (Rattus norvegicus) for mapping of disease-resistant genes

Wild rat representing a disease-resistant phenotype and genotype, was used in a crossing study with spontaneously hypertensive rat (SHR) to search for quantitative trait loci (QTL) affecting blood pressure. Therefore, one mal e wild rat was crossed with SHR females and F1 hybrids were transferred in a pathogen free environment by wet-hysterectomy and backcrossed onto hypert ensive SHR rats resulting in first backcross hybrids (BC1). Considering tha t the F1 hybrids are not uniform, as are the cross hybrids of inbred rat st rains, we selected 72 BC1 progeny of one F1 female, which were characterise d for systolic blood pressure, measured by tail cuff method and were geneti cally analysed using 200 microsatellites covering the whole genome. We foun d suggestive linkage of blood pressure to region on chromosome 2 flanked by D2Mit8 and Fgg loci (lod score 2.3). In addition, possible interaction bet ween genes on chromosomes 7 and 3, X and 3, 14 and 3, 13 and 11 was describ ed, indicating that blood pressure development in the SHR might be the resu lt of interacting genes.