Studies On SNPs Of Candidate Genes INHBA And INHBB For Fecundity Of Goat

The purpose of this study was to detect single nucleotide polymorphisms(SNPs) within INHBA gene and INHBB gene,to analyze the genetic structure of three goat breeds,and to investigate the effects of the two genes on litter size of Jining Grey goats. Based on the bovine DNA sequences in GenBank,four and two primer pairs for INHBA gene and INHBB gene,respectively,were designed for PCR.Amplified regions included Exon 1,Exon 2 of INHBA gene.SNPs of INHBA and INHBB from three different goat breeds were detected by single strand configuration polymorphisms (SSCP).The genetic structure of the three populations at polymorphic loci,and the associations of the litter size of Jining Grey does with the two genes were also explored. The results are as follows:1.By 6 pairs of primers,only 2 SNP sites were tested,which located respectively at exon 2 of INHBA(named locus A)and exon 2 of INHBB gene(named locus B).2.At locus A,the mutation site was at 583 bp of the exon 2,which resulted in allele A and B.Sequencing revealed that allele B was caused by T→C mutation.This mutation resulted in proline→leucine(Pro→leu)substitution.Genotypes AA,AB and BB were detected in Jining Grey goats and Angora goats,genotypes AB and BB in Inner Mongolia Cashmere goats.AA,AB and BB genotype frequencies were 0.4786, 0.4143 and 0.1071 respectively in Jining Grey goats.The difference of the kids among the different genotyes In Jining Grey goat,showed that the kids of genotype AA increased 1.14(P＜0.01)than that of genotype BB and 0.42(P＜0.05)than that of genotype AB respectively;the kids with genotype AB increased 0.72(P＜0.05)than with genotype BB.3.At locus B,the mutation site was at 840 bp of the exon 2,which resulted in allele C and D.Sequencing revealed that allele D was caused by A→G mutation.This mutation resulted in His→Arg substitution.Genotype CC,CD and DD were detected in Jining Grey,genotype CD and DD in both Inner Mongolia Cashmere goats and Angora goats.Genotype frequencies of CC,CD and DD were 0.0685,0.5000 and 0.4315 respectively in Jining Grey goats.In Jining Grey goat,the difference of the kids among the different genotyes showed that the kids of genotype CC increased 0.73(P＜0.05) than genotype CD and 0.84 than that of genotype DD respectively,the kids with genotype CD increased 0.11 than with genotype DD(P＞0.05). 4.The genetic polymorphism in 3 breeds at locus A and B was rich.Genetic difference at locus A and B between Jining Grey goat and other two goat breeds was significant,which was associated with the fecundity of goat.Therefore,INHBA gene and INHBB gene may be regarded as major genes for the fecundity of goat,or linked with the major genes influencing the fecundity of goat.It may be feasible to implement the marker assisted selection using the two SNP sites.