The CDNA Cloning And Polymorphism Analysis Of Fgf5 Gene In Goat And Sheep

FGF5 is one of member of the FGF superfamily. It is expressed in central nervous system and skin follicle cells and functions as a negative regulator of follicle growth in rat and mouse. This study was designed and aimed to identify the single nucleotide polymorphisms (SNPs) of FGF5 gene in various breeds sheep including China merino, Tibet sheep, xiao wei han sheep and hu sheep; also in different goat including Liaoning cashmere, Inner Mongoliar cashmere goat and Wendeng dairy goat. The FGF5 cDNAs were cloned from gaot central nervous system tissue and sequence analysis indicated that nucleotide acid homologies between goat human and between goat and rat were more than 85%, respectively. Amino acid similarities between goat and human were 87% and between gaot and mouse were 83%. Just like other members of FGFs superfamily, FGF5 protein also has a signal sequence ,at same time its protein has higly similar sequence about 120 Amino acid in central core sequence with other breed. Tissue specific expression of the FGF5 gene was also investigated in cashmere goat by RT-PCR analysis. The results showed that FGF5 gene was expressed in different time of the tested skin tissues, including anage and telegon. But unlike in rat and mouse we only found one kind mRNA, that is long spice mRNA, but other kind spice short mRNA (FGF5s) was not investigated. The 4 pairs of primers for FGF5 gene were designed based mouse and human genomic sequence. Two SNPs were identified in the goat and sheep FGF5 gene by PCR-SSCP and sequencing. Both of them were in the exon1 region in different breed. The sequence data showed that one of the three SNPs localized in the first primer region was due to one single point mutations (G→T), other single point mutations were C→T in primer2. Population genetic analysis in sheep indicated that genotype frequency of the P1 SNPs in xinjiang meilinu were quite different from other tested sheep breed. Frequency of the BB genotype was much higher in xinjiang meilinu while the AA genotype was much lower than other breed. The genotype frequency of P1 was significantly different in the tested sheep lines (P<0.01). All the population were in Hardy-Weinberg equilibrium state.For primer 2, frequency of the EE genotype in tibet sheep was higer than those in the other lines, Frequency of allele E in primer2 (P2) in Tibet sheep was higher than that of other breed. All the population were in Hardy-Weinberg equilibrium state except China merino. Population genetic analysis in goat indicated that genotype frequency of the P1 SNPs in different goat were similar. Frequency of the BB genotype was all much higer than AA genotype. The genotype frequency of P1 was insignificantly different in the tested goat lines (P>0.05). All the population were in Hardy-Weinberg equilibrium state.For primer1; For primer 2 frequency of the EE genotype in both cashmere was higer than those in Wendeng dairy goat, Liaoning cashmere population were not in Hardy-Weinberg equilibrium state.