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 male wild rat was crossed with SHR females and F1 hybrids were transferred in a pathogen free environment by wet-hysterectomy and backcrossed onto hypertensive SHR rats resulting in first backcross hybrids (BC1). Considering that the F1 hybrids are not uniform, as are the cross hybrids of inbred rat strains, we selected 72 BC1 progeny of one F1 female, which were characterised for systolic blood pressure, measured by tail cuff method and were genetically analysed using 200 microsatellites covering the whole genome. We found suggestive linkage of blood pressure to region on chromosome 2 flanked by D2Mit8 and Fgg loci (lod score 2.3). In addition, possible interaction between genes on chromosomes 7 and 3, X and 3, 14 and 3, 13 and 11 was described, indicating that blood pressure development in the SHR might be the result of interacting genes.