GENETIC-ANALYSIS OF TRIPLOIDY IN A SELECTED LINE OF CHICKENS

We investigated the pattern of inheritance of maternal meiotic errors responsible for a high frequency of triploid progeny in a selected lin e of chickens, For the genetic analysis, F-1 and backcross populations were produced from crosses between normal diploid individuals of the triploidy line and a control line, Triploid embryos were produced by 3 5% and 67% of reciprocal F-1 females and by 24% and 67% of reciprocal backcross females, These results exclude autosomal recessive and sex-l inked recessive or sex-linked dominant inheritance, A single autosomal dominant gene is also not likely to be responsible, However, the resu lts are consistent with the determination of triploidy by a single aut osomal gene with no dominance, and an even better fit is obtained by t wo loci, an autosomal gene with no dominance and a sex-linked gene, Th e results cannot exclude a multifactorial mode of inheritance, but the rapid response to selection for triploidy and consistent expression o f the meiotic errors in different genotypes suggest that meiotic mutat ions at one or two loci are the most plausible genetic basis for the t rait.