Association Of FGF2 Gene Polymorphisms With Body Measurements And Meat Quality Traits In Qinchuan Beef Cattle

Fibroblast growth factor-2(FGF2) is one of the FGFs family, existed in many kinds of cells/tissues, participated in a variety of physiological processes. and, it might be a candidate gene that would affect the production traits of beef cattle. For exploring the effect of the FGF2 on growth traits of Qinchuan beef cattle, to accelerate the selection and improvement on Qinchuan beef cattle breeding, in this study, combined with modern bio-information technology, the bioinformatics,structure and evolutionary information of FGF2(belongs to FGFs family), was analyzed. It was detected the all exon region single nucleotide polymorphism of FGF2 gene in 384 Qinchuan beef cattle about 18-24 months old, and, analyzed each SNP loci related to population genetic information and equilibrium after genotyping.The association analysis was carry out to evaluate the FGF2 genetic variations on growth traits of Qinchuan beef cattle. So that, there was to explore the gene function on molecular markers, for further breeding of Qinchuan beef cattle. The results were as follows:1. Bioinformatics analysis of FGF2 gene showed that The free energy of FGF2 mRNA secondary structure of cattle is about-1752.60 kcal/mol; a FGF2 protein contains 20 kinds of amino acids and showed strong hydrophilicity; there was no transmembrane protein structure; FGF2 protein of bovine was closely related to the goat and the sheep, and the wild boar was the most distant.2. The SNPs were detected, and showed that there were four SNPs sites in Qinchuan beef cattle FGF2 third exon totally, which were located at 54740bp(A> T),54758bp(A> C), 56809bp(T> C) and 59443bp(C> T).3. The association, between FGF2 and Qinchuan beef cattle growth traits, were described: the A54740> T and A54758> C growth traits mutant population mean was less than the wild-type group traits, these mutation would reduce the body length,body height, chest deep traits(P <0.05), belongs to unfavorable mutation on body size traits; wherein, the AA type traits(at A54740>T and A54758> C locus site,respectively.) for body size were dominant genotype, with character maximized. The T56809> C and C59443> T growth traits mean was larger than the wild-type group traits, this mutation would increase body length, body height, chest deep traits(P<0.05), belongs to beneficial mutation on body size traits; wherein, the CC and TT genotype(at T56809 > C and C59443> T loci site, respectively.) for body size traits were predominant genotypes, with the highest property values.The AA type(A54740>T) on intramuscular fat trait was the predominant genotype(P <0.05), with the highest value trait; the other sites SNPs and intramuscular fat trait are irrelevant; the CC type(A54758> C) and TT type(C59443>T)on eye muscle area trait were predominant genotypes(P <0.05), with the highest property values, independent of the other sites SNPs traits and loin eye area;in addition, at C59443>T locus, TT type was dominant genotype on back fat thickness trait(P <0.05), independent of the other sites SNPs and back fat thickness.4. The linkage disequilibrium tests: There were discovered some strong linkage effect of these four SNPs, by linkage disequilibrium test; taking the four sites in linkage disequilibrium state for further study found that these four SNPs could be composed of six haplotypes and could be genetic, which HAP1-AATC- haplotype frequency was 59.8%, the highest, HAP5 haplotype –TCCT- followed(frequency24.2%), and HAP3 haplotype-ACTC- occurred at small probability(frequency low frequency 9.4%), the rest of the other haplotype.5. The Real Time PCR results of FGF2 mRNA in different tissues was shown that, the expression of lung, kidney and muscle were at a high level. Inversely, the expression of reticulum, omasum and abomasum were at the low level. And, the FGF2 of heart, liver and fat had the middle abundance. Moreover, the most abundant expression of FGF2 was in lung, and the lowest was in abomasum, respectively.To sum up, several SNPs mutations in FGF2 have an impact on growth traits of Qinchuan beef cattle. so that, the FGF2 could be considered as a candidate reference gene for the further breeding of Qinchuan beef cattle.