Association Of FSH?/FSHR Gene With Ovarian Development And It's Polymorphism In Hu Sheep

Hu sheep has the characteristics of adaptability,fast growth,early maturity,sensation in the four seasons,and high reproductive yield.Follicular stimulating hormone(FSH)is an important hormone that promotes follicular development.The hormone exerts physiological effects through the adenylate cyclase-cyclic adenosine monophosphate(cAMP)pathway mediated by its receptor FSHR.In this study,3 ewes of the 7 stages from birth to 6 months of age as research materials.The body weight,ovary weight and size,and uterine weight of the ewes of each month were measured.The ovarian tissues of each month's ewes were embedded in paraffin and sectioned,and then the sections were stained with HE.The changes of ovarian tissue structure were observed under an orthoscopic microscope and counted the total number of follicles,preantral follicles and antral follicles.The distribution of FSH? and FSHR in the ovary was detected by immunohistochemistry.Fluorescence quantitative PCR was used to detect the expression levels of FSH? and FSHR in ovary and pituitary at each age.Single nucleotide polymorphisms(SNPs)of FSH? and FSHR genes in Hu sheep were detected by PCR amplification and sequencing.According to the ewes' lambing records,the individuals with two tails in the normal distribution were selected as the high-yield group and the low-yield group.The genetic parameters of the SNPs of FSH? and FSHR genes in the two groups were calculated,and these SNPs were compared between the two groups by chi-square test.The aim of this study was to investigate the relationship between FSH? and FSHR genes and ovarian development of Hu sheep,and the influence of FSH?/FSHR gene polymorphism on the number of litters in Hu sheep,and provide theoretical basis for improving the breeding ability and marker-assisted selection of Hu sheep.The results obtained are as follows:1.During the period from the first birth to the age of 6 months,the weight and size of the body weight and the ovaries' size at 2 months of age increased the fastest,and a large number of antral follicles began to appear at 2 months of age.2.FSH? distribution was observed in oocytes,granulosa cells and zona pellucida in follicles.FSH? mRNA was expressed in ovary and pituitary gland at each age.The expression of FSH? in ovary at newborn and 1 month of age were higher than that in other months,and the difference was not significant(p > 0.05).In the pituitary,the expression of FSH? at birth was lower than that at other months,and the difference was not significant(p > 0.05).3.The oocytes and granulosa cells in the follicles have a distribution of FSHR,but the zona pellucida has no FSHR.FSHR mRNA was expressed in the ovaries and pituitary gland of each month's age,but the expression level in pituitary was low,and the expression levels were increased by 30%,173% and 192% at 4,5 and 6 months of age,respectively.The expression level of FSHR in the ovary increased rapidly from the age of two months,reached the highest at the age of four months.4.g.40 T > C,g.78 T > C,g.99 G > T and g.101 A > G at the FSHR gene showed significant differences in genotype frequencies between the high-yield groups and low-yield groups(p < 0.05),where in g.78 T > C,g.99 G > T and g.101 A > G were linked,and the haplotypes formed were significantly different in the high-yield and low-yield groups(p < 0.05).It is speculated that this haplotype is associated with high-yield traits..Above all,through the measurement of body weight and size,ovary weight and size,and the staining of ovarian tissue sections,the growth process of the body,the ovarian and follicular development process of the ewes before the age of 6 months were determined.Using immunohistochemistry and real-time PCR,it was confirmed that FSH? is expressed in the ovary.It is speculated that the primordial follicle at the time of birth will secrete FSH?,but further research is needed.It was also confirmed that FSHR is distributed in the primordial follicles.The g.759 G > A screened in the FSH? gene may be associated with high-yield traits,and the linkage block formed by seven sites in the FSHR gene may be associated with high-yield traits.The results of this study suggest that the body of Hu sheep enters the rapid development stage from one to two months old,providing a basis and clear research direction for subsequent related research.