Molecular Cloning, SNP Detecting Of Goat MFG-E8 Gene And Their Associations With Economic Traits In Dairy Goats

Reverse transcriptase polymerase chain reaction (RT-PCR), DNA pool, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing methods were employed to obtain the complete CDS sequence of MFG-E8 and screen for the genetic variation in MFG-E8 gene in 668 Chinese dairy goats. Association analysis between MFG-E8 gene polymorphisms and some economic traits in 2 populations was studyed.The main results were as follows:1.The CDS of MFG-E8 gene was gained (GU593981).The full length of the CDS was 1287 bp, which encoded a polypeptide of 426 amino acids.The MFG-E8 protein contains two EGF domains and two F5/8 type C domains.The homologies of cDNA nucleotide sequence of MFG-E8 gene with the counterparts of bovine (NM₁76610), swine (NM₀01122984), mouse (NM₀01045489) and homo(NM₀05928) were 94%,86%,76%,70%, and the homologies of peptide sequence were 91%,81%,70%,62%, respectively.2.The polymorphism of 5'UTR region and 9 exon was studied, the results revealed four novel mutations:NC₀07319:g.843delA, g.6417delC,g.12892T>C and g.12996A>C,They are in 5'UTR region, the 4th intron, the 7th exon and the 7th intron, respectively. The 12892T>C was named as EcoRV locus, identified a samesense mutation at the 7th exon in the MFG-E8 gene:AAT (Asp)>AAC (Asp), which is at position 310aa of the MFG-E8 (426aa) protein; the 12996A>C,named as Haeâ…¢locus. Moreover, the frequencies of the MFG-E8-A allele of the UTR locus in the populations analyzed were 0.461 and 0.441 for the Xinong Saanen, and Guanzhong populations, respectively;the frequencies of the MFG-E8-C allele of the 14 locus in the populations analyzed were 0.57 and 0.578 for the Xinong Saanen, and Guanzhong populations, respectively the frequencies of the MFG-E8-T allele of the EcoRV locus in the populations analyzed were 0.541 and 0.570 for the Xinong Saanen, and Guanzhong populations, respectively and the frequencies of the MFG-E8-A allele of the Haeâ…¢locus in the populations analyzed were 0.527 and 0.625,respectively.3.Significant statistical differences in genotypic frequencies for the four loci of the MFG-E8 gene implied that the DA and EcoRV loci are associated with milk fat yield (DA locus:P= 0.000;EcoRV locus:P= 0.001)and total solid (DA locus:P= 0.002;EcoRV locus: P=0.007) in the Xinong Saanen dairy goat. There is no significant association between the four loci and height at withers, body length, heart girth and milk yield.