| Myostatin (MSTN), formerly known as growth differentiation factor-8, which was discovered in 1997, is a member of the transforming growth factor-beta superfamily that functions as a negative regulator of skeletal muscle development and growth in mammals. MSTN gene share a similar structure and a relatively conserved amino acid sequence with the other superfamily members which has 3 exons and 2 introns. Myostatin not only expresses in skeletal muscle, but also can express in Purkinje fibers and heart tissue. Research indicated, that in vivo regenerating rat skeletal muscles showed a characteristic time-dependent expression of myostatin mRNA , and in vitro experimentation suggested that functional innervation is noprerequisite for myostatin expression.The mutation of MSTN gene leads to the so-called double-muscling phenotype which have found in several mammalian species including cattle, sheep and pig. Therefore,the objective of present study were to detect the distribution of MSTN mRNA in different tissues by RT-PCR, and detected the polymorphisms of the MSTN genes by PCR-SSCP (single-strand conformation polymorphism) in the population of landaise goose and analyzed the genetic correlation between the polymorphisms and growth and carcass traits by SPSS.In the experiment of distribution of MSTN mRNA in tissues of landaise goose, 20 landaise goose with the same incubation, 70 days old, similar weight, healthy, were killed by carotid artery bloodletting.Within 30 minutes post-slaughter, 13 tissues were collected: brain, heart, liver, spleen, lung, kidney, pancreas, abdomen adipose, subcutaneous adipose, thorax muscle, leg muscle. Samples were snap-frozen in liquid nitrogen and subsequently stored at -80°C.The distribution of MSTNmRNA in different tissues of landaise goose was detected by RT-PCR. The results shown: the MSTN mRNA was detected in brain, heart, spleen, pancreas, abdomen adipose, subcutaneous adipose, thorax muscle, leg muscle,not in 3 other tissues. The wide spectrum of MSTN gene expressing in tissues reveals that MSTN may have multiple physiological functions in landaise goose. The polymorphism of the MSTN gene in landaise goose was analyzed by PCR-SSCP. The results showed that the polymorphisms were not detected by PCR-SSCP in the exon1 of the MSTN gene. And two alleles, A, and G, three genotypes, AA, AG, and GG, were detected in the exon3 of the MSTN gene. The polymorphism fragments were cloned and sequenced. The sequencing results indicated that there was one single nucleotide mutation: A→G in the exon3 of the the MSTN gene. The genetic correlations were obtained between genotypes of the exon3 of MSTN gene and growth and carcass traits by the least square analysis.The results indicated that different MSTN genotypes significantly affected overfed gain, abdomen fat rate, whole eviscerated weight, live weight, abdomen fat weight, leg muscle rate, sebum thick. Overfed gain for AA genotype on MSTN was significantly higher than for AG and GG (P<0.01), and AG genotype on MSTN was significantly higher than for GG (P<0.05). whole eviscerated weight and abdomen fat rate for AG and GG genotype on MSTN was significantly higher than for AA (P<0.05). live weight and abdomen fat weight for AG and GG genotype on MSTN was significantly higher than for AA (P<0.01). leg muscle rate for GG genotype on MSTN was significantly higher than for AG and AA (P<0.05). sebum thick for AA genotype on MSTN was significantly higher than for AG and GG (P<0.01). Other traits were not significantly affected. It could be preliminarily deduced that MSTN gene was probably a major gene or a QTL linked gene which associated with growth and carcass traits in landaise goose. |
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