Evidence for Complementary Action of tvb and tve Genes that control Susceptibility to Subgroup E RNA Tumour Virus in Chickens

Chick embryos of two test-crosses, involving three inbred lines, 7-2, E and Reaseheath C, of Houghton Poultry Research Station, were challenged (on to the chorioallantoic membranes) with RSV(RAV 2) of subgroup B and RSV(RAV 0) of subgroup E. Genetic analysis for B-and E-susceptibility indicated that the average E-susceptibility in the chicken line E carrying the e^s gene can be increased or decreased by addition or subtraction, respectively, of the b^s gene. The results of this study are a better fit to a two-gene model with complementary gene action than to a single gene model of multiple allelism of the tvb-locus with pleiotropic gene action.