Genetic basis of fluff clarification in day old chickens of Italian Partridge chicken breed

In autosexable breeds and populations of chicken the differences in fluff coloration between male and female day old chicks depend on the gene dose. In comparison to this in commercial crosses and strains those differences depend on different alleles. As a rule, such differences are highly variable and sexing accuracy is not sufficient enough to ensureefficient sex separation. There is possible to increase sexing accuracy by enhancing of expression of the genes, controlling fluff clarification. Their effect depends on the genetic environment. Our previous investigations revealed, that by selection of genes-modificators. There is possible to entrance difference in fluff melanization between day old males and femailes. in chicken Italian Partridge breed from the Bioresource collection of RRIFAGB there was found a trait of fluff clarification among day old chicks. The was suggested that is was described in the literature sex-linked gene "Li". Its dominant allele clarifies pheomelanine part of fluff pattern in day old chicks. To check this hypothesis there were carried several crossings between cocks and hens of the Italian Partridge breed. One group consisted of the parents, which had light fluff coloration in one day age. The another group consisted of the cocks, which had light fluff coloration while day old hens had standard fluff coloration. The carried out studies demonstrated that the trait found in the Italian Partridge breed, most likely was determinied by a sex-linked gene. Among the of the chicks with standard fluff coloration on the ratio hens: cocks was 2:1. The results of fluff coloration distribution among progeny of the parents with light fluff enable to suggest, that the gene controlling this trait is not completely dominant, because in case of complete dominance all progeny of light-fluffed parent would have light fluff, while in the second group fluff coloration ratio would be 1:1. Also one can assume, that the trait of fluff coloration is controlled not by only one gene and more light fluff coloration is a result of the additive effect. The investigations of the genetic basis this trait are important for its possible application in the autosexable breeds and populations.

chickens auto sexuality, accuracy of sexing, pheomelanine color, degree of melanization, modifier genes, gene dose

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