Abstract
The LEC rat, a mutant strain, spontaneously develops heritable hepatitis due to copper accumulation caused by mutation of copper transporting ATPase gene (Atp7b). Iimmunodeficiency and radio-sensitivity had also been reported. We, firstly, analyzed linkage between radio-sensitivity and the mutation responsible for LEC hepatitis in hybrid animals of cross with F344 rats. Results demonstrated the absence of any significant association. Radio-sensitive rats were twice as numerous as their radio-resistant counterparts, suggesting possibility of control by two or more recessive genes. In order to select radio-sensitivity gene of the LEC rat, we wished to develop congenic line of F344 rats using a phenotype-driven breeding protocol: rats of each backcross generation were mated with LEC rats and their offspring were irradiated with 4.5 Gy X-rays, which dose cause death in LEC rats but did not in F344 rats. Lately we also combined using genomic-wide genotyping in each backcross generation and their progeny to select heterogeneous rat. Backcross exceeded 16 generations. This radio-sensitivity gene locates on chromosome 4. [J Radiat Res 44:434 (2003)]
