GENETIC-ANALYSIS OF 4 DIFFERING TRAITS (MHC HAPLOTYPE, TUMOR RESPONSE, CD4CD8 RATIO, EV 17) IN CB AND CC CONGENIC CHICKENS

Two closely related inbred lines of chickens, CB and CC, were compared for major histocompatibility complex (MHC) haplotype, response to tum ors induced by Rous sarcoma virus and CD4:CD8 ratio. Genetic analysis showed that all the above traits were associated with the MHC. In all CB chickens, we found an additional endogenous virus, ev 17, a provira l sequence lacking in all tested CC animals. From our analysis and dat a from the literature, we presume that the presence of ev 17 in CB chi ckens is probably caused by gene duplication of ev 1 with extensive nu cleotide alterations. Our analysis with (CB x CC) x CC backcrosses dem onstrate that ev 17 is not linked to the chicken B complex. From our e xperiments, we conclude that inbred CB and CC chickens differ in MHC a nd ev 17, and we established additional congenic inbred lines with and without the proviral locus ev 17.