Study On Polymorphism Of Inhibin-alpha Gene And Its Relationship With High Prolificacy In Small Tail Han Sheep

Inhibins are gonadal glycoprote in hormones belonging to the transforming growth factor-β superfammily that act to suppress pituitary follicle-stimulating hormone synthesis and secretion .Based on the genetic polymorphism of INH- α gene ,we try to link this candidate gene with the high productivity of Xiaoweihanyang(XWHY), to further provide scientific evidence for the basic genetic research on XWHY"s high productivity. Applying the powerful PCR-SSCP technique and sequence to analyze the polymorphism of INH- α gene ,we divide our samples into 2 group, one group is the blood sample of 150 XWHY with littering record; another group is the blood sample of 4 sheep breeds without littering record. The result are as the following:(1) The optimum method of PCR-SSCP about INH- α gene has been established. Although there is no report about the polymorphism of INH- α gene, our research try to find out the best conditions of PCR-SSCP through designing four primers of INH- α gene.(2) Using the method of our research, we examine the gene of INH- α by PCR-SSCP technique ;the loci of has mutation in five breeds. In the loci of, there has mutation in high reproductive breed, but no mutation in low reproductive breed.(3) Cloning and sequencing the PCR products which have mutations, we find thatthe loci of INH- α -exonl has the mutation at 877bp(T→C),although it has the mutation ,it can not lead to the change of amino sequence; in the loci of INH- α -1,there are two mutations ,one is at 62bp (A→C),and the other is at 73bp (C→T),and the mutations related to the transcription and translation of INH- α gene properly.(4) Least squares analysis of litter size in Small Tail Han sheep show that different genotype of INH-α -1 have significant effects on productive trait, the mutation of homozygote(DD) 0.70 (p<0.01) and heterozygote(CD) 0.58(p<0.01)were more than CC genotype respectively; in the INH-α -exonl loci, the AB genotype 0.87(p<0.01) were more than AA genotype.(5) examined the difference for exonl of inhibin-a gene distribution in five sheep breeds by X2 test. The distribution of between the high prolificacy breeds (Small tail Han and Hu sheep) and the low prolificacy breeds (Dorest, Texl and GermanMerino) is very remarkable (p<0.01). The distribution in high prolificacy breeds is also remarkable, but it is not remarkable in the low prolificacy breeds (p>0.05).