Albino Mutation in Chickens

Albino Mutation in Chickens - Brazilian Journal of Poultry...

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Brazilian Journal of Poultry Science Revista Brasileira de Ciência Avícola ISSN 1516-635X Jul - Sep 2008 / v.10 / n.3 / 153 - 156 153 Inheritance of a New Albino Mutation in Brazilian Free-range Black Chickens Mail Address Keywords Author(s) Arrived: November/2006 Approved: August/2008 ABSTRACT A genetically recessive albino mutation, which inhibits pigment development in the eyes, skin, and feathers of domestic chickens from Brazil, is described. This mutation appeared in a flock of completely black chickens of a private breeder. There are no information on the origin, breed, or specific line of the birds. Pigment inhibition is apparently complete in the feathers and eyes. Bird sight is very impaired, but no histological examination was carried out. Ratios obtained in F2 and backcrossed birds indicate that a single autosomal recessive gene is responsible for the condition. The data suggest that the absence of melanin in the eyes, skin, and feathers (symbol cc) is a mutation of the pigmented C wild gene. INTRODUCTION The term "albinism" comprises a wide range of traits, all of which result from pigment production or distribution disorders. The phenotype is due to a defect in melanin synthesis that results in partial or complete absence of this pigment in the skin, hair, feather, and eyes. The trait can be inherited by autosomal (recessive or dominant) or Z-linked (X- linked in mammals) inheritance. Several different vertebrates may present the phenotype due to a defect in melanin synthesis arising from a gene mutation. To date, about 60 different mutations were isolated in many different species of vertebrates. In most domestic animals, albinism is caused by recessive autosomal or X-linked inheritance, except for the dominant autosomal gene in horses, in which the homozygous form is lethal. Total or complete albinism is described in cats (Turner et al. , 1981) and Suffolk sheep as the structural locus for the tyrosinase gene (Tobita-Teramoto et al. , 2000). In the chicken, there are different mutations, resulting in different degrees of depigmentation, and consequently several types of albinism. According to Smith Jr. (1990), there are two general types of pigments in chickens : melanin and carotenoids. Melanin (a natural pigment) plays a major role in the color of feathers, skin, shanks, beak, and eyes, while carotenoids (xanthophyll) are responsible for the yellow color of skin, fat and egg yolk. These two types of pigment can interact with each other and/or other cell types to produce a variety of shank and eye colors, as well as different feather shine levels. The inheritance of pinkeye was first described by Warren (1940) in White Plymouth Rock chickens, indicating that pinkeye was due to an autosomal recessive gene (pk). Roberts et al. (1952) studied a "red- eye" mutation, which is a recessive autosomal gene, and is less viable than dark-eye in the chicken. Both mutations cause sight impairment.
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Albino Mutation in Chickens - Brazilian Journal of Poultry...

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