Analysis Of CAST And MyoD Gene Polymorphism And Its Correlation With Meat Traits In Bamei Sheep

The aim of this study was to analyze the polymorphism of CAST (exon 6 and 3’-UTR region) and MyoD gene (exon 1 and 5’flanking region) in 110 Bamei sheep by using PCR-SSCP method.Twenty-six 12-month female Bamei sheep were selected to study the correlation between different genetypes and meat traits.The objectives of this study were to provide a theoretical foundation for the further improvement and promotion of Bamei sheep and the two genes as the marker-assist-selection of mutton quality traits. The results of this investigation demonstrated that products amplified by primer CAST-P1, CAST-P4, CAST-P5, CAST-P6, MyoD-T1 and MyoD-T5 had polymorphisms. The primer of CAST-P6 was in the high polymorphism.The other 5 pairs of primers were all in the midrange polymorphism. The direct sequencing data indicated that there was two mutation have been found in primer CAST-P1 (56bp,184bp), which had three genotypes (AA, AB, AC).Primer CAST-P4 has four mutation sites,including three replaces of nucleotide (117bp、131 bp,201 bp) and two bases deletion (105-106bp),which resulted products amplified by CAST-P4 had three genotypes (AA, BB, BC).There was one mutation have been found in primer CAST-P5 (32bp), which resulted CAST-P5 had two genotypes,the two genotypes were identified as AA and BC.There were four replaces of nucleotide (135bp,142bp,148bp,151bp),which resulted products amplified by CAST-P6 had three genotypes (AA, BB, BC).primer MyoD-T1 has two mutation sites(A14.,G118A), which resulted products amplified by MyoD-T1 had two genotypes (AA, AB).The relationship with carcass and meat quality traits revealed that different genotypes were related with slaughter weight, red/green colours (a*) of biceps femoris and pH1 of triceps in CAST-P1 site (P<0.05);In CAST-P4 site, there were significant influences of slaughter weight,carcass weight and lightness (L*)in longissimus dorsi of three genotypes (P<0.05);In fragment of CAST-P5 site, there were significant influences of pHi value, meat colors(a*, b*, L*) in three genotypes (P<0.05).There was significant influences of shear force in longissimus dorsi of three genotypes (P<0.05);In CAST-P6 site, significant differences were found in shear force, red/green colours (a*) and lightness (L*)of longissimus dorsi position in two genotypes(P<0.05), tenderness of BC genotype was better. Significant influence was found in red/green colours (a*) of supraspinatus position(P<0.05), red/green colours (a*) of BC genotype was better than AA genotype;In fragment of MyoD-T1 site, statistical analysis revealed higher value in red/green colours (a*) of triceps and the lightness (L*) of supraspinatus(P<0.01), high value in lightness (L*), pHi of triceps and biceps femoris(P< 0.05);In MyoD-T5 site, significant influences were found in shear force of triceps position, b value(b*) and pHi of semitendinosus,pHi of supraspinatusin in two genotypes.All these findings suggested that a direct interaction between the two genes and the meat traits of Bamei sheep,which needed further development and utilization.