Investigation of polymorphisms of myogenic factors and myostatin genes as molecular markers for quantitative traits in Gallus gallus. / Investigação de polimorfismos nos genes dos fatores Miogênicos e Miostatina como marcadores moleculares para características quantitativas em Gallus gallus.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The aim of this work was to identify polymorphisms in five candidate genes (MyoD, Myf5, Myogenin, MRF4 and Myostatin) which act in chicken muscle development and evaluate the effects of its allelic variants on growth and muscle development quantitative traits. MyoD and Myf5 are essential for the determination of the myogenic lineage of muscle precursor cells in early stages of myogenesis, whereas myogenin and MRF4 are required for the final differentiation of these cells. Myostatin acts as a potent negative regulator of skeletal muscle growth during myogenesis and continues to be expressed in adult animals. PCR products of these five genes were cloned and sequenced from DNA pools of parental individuals from two distinct lineages developed by Embrapa - Suínos e Aves, a broiler sire line (TT) and a layer line (CC). The polymorphisms identified were validated and genotyped in a F2 experimental population originated from a crossing of TT line sires ands CC line dams. Polymorphisms of Myostatin, Myogenin and MyoD genes were genotyped to evaluate their effects on quantitative traits. The effects of Myostatin and MyoD polymorphisms were not significant on any traits. Among the polymorphic sites detected in the myogenin gene one, identifyed as T455C, was significantly associated with the following traits: body weight at 42 days of age (P = 0,0263), body weight gain between birth and 42 days of age (P = 0,0291), body weight gain between 35 and 42 days of age (P = 0,0368), carcass weight (P = 0,0245), weight of drums (P = 0,0099), residual carcass (P = 0,0056), abdominal fat (P = 0,0320), liver (P = 0,0373) and lungs (P = 0,0262). New investigations should be conducted to validate this polymorphism as a possible genetic marker for selection of chickens with increased muscle development potential. Although many polymorphisms were detected in Myf5 and MRF4 genes, it was not possible to establish ideal conditions for their genotyping.

ASSUNTO(S)

crescimento e desenvolvimento avicultura polymophism growth and development molecular marker biotechnology marcador molecular biotecnologia genes poutry breeding genes polimorfismo

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