| AS two insulin-responsive compartments, SH2B1 and TBC1D1 are key functional proteins in insulin-stimulated glucose intake. In the present study, the SNPs of partial SH2B1 mRNA sequence and integral TBC1D1 mRNA sequence were firstly detected by directing sequencing, and then the candidate SNPs were genotyped by HRM, PCR-RFLP and biology mass spectrum in total of 722 in five breeds. Association analysis between SNPs of SH2B1 and TBC1D1 genes and growth traits, carcass traits and meat quality traits was conducted by the least-squares method; According to the results and the importance of mutations, SH2B1 gene was screened and tested mRNA relative expression in hepatic of 35 day of age,56 day of age and 70 day of age, respectively. The relationship of mRNA relative expression in different period and different genotypes were analysed. The experiment results were as follows:(1) Two SNPs located in 3’UTR were detected in SH2B1 gene (r.*464 T>C and r.*749 G>A); 12 SNPs were detected in TBC1D1 gene, among them, seven synonymous mutations (c.2451G>A, c.2514A>Q c.2535G>A, c.2589G>A, c.2763T>C, c.2844T>C, c.2937G>T) located in TBC domain, four synonymous mutations (c.l53T>C, c.252A>G, c.564G>A, c.591G>A) and one non-synonymous mutations c.214G>A (Gly72Arg) located in two PTB domains, respectively. According the biological function of 3’UTR region in mRNA and non-synonymous mutations, r.*464 T>C mutation in SH2B1 gene and c.214G>A in TBC1D1 gene were choosed to study in rabbit.(2)Three genotypes CC, TC and TT of r.*464 T>C of SH2B1 gene were detected in New Zealand rabbit (NZR, n=288), Champagne rabbit (n=74), Ira rabbit (n=85) and Tianfu black rabbit (n=56). The genotype frequency of genotype CC, TC and TT in New Zealand rabbit were 0.177,0.576 and 0.247, respectively. The genotype frequency of genotype CC, TC and TT in Champagne were 0.24,0.554 and 0.203, respectively. The genotype frequency of genotype CC, TC and TT in Ira were 0.083, 0.435 and 0.482, respectively. The genotype frequency of genotype CC, TC and TT in Tianfu black rabbit were 0.089,0.661 and 0.250, respectively. Allele T was the predominant allele in New Zealand rabbit, Ira and Tianfu black rabbit with frequency 0.535,0.700 and 0.580, respectively. Allele C was the predominant allele in Champagne with frequency 0.520.(3)Three genotypes AA, GA and GG of c.214G>A of TBC1D1 gene were detected in European white rabbit (EWR, n=205), NZR (n=286),Champagne (n=81), Ira (n=87) and Tianfu black rabbit (n=61). The genotype frequency of genotype AA, GA and GG in European white rabbit were 0.639,0.278 and 0.083, respectively. The genotype frequency of genotype AA, GA and GG in New Zealand rabbit were 0.489,0.357 and 0.154, respectively. The genotype frequency of genotype AA, GA and GG in Champagne were 0.012,0.086 and 0.902, respectively. The genotype frequency of genotype AA, GA and GG in Ira were 0.011,0.138 and 0.851, respectively. The genotype frequency of genotype AA, GA and GG in Tianfu black rabbit were 0.016,0.197 and 0.787, respectively. Allele A was the predominant allele in NZR and EWR with frequency 0.778 and 0.668, respectively. The c.214G>A suggested the moderate polymorphism in the two breeds. Allele G was the predominant allele in Champagne, Ira and Tianfu black rabbit with frequency 0.944, 0.919 and 0.885, respectively. The c.214G>A showed the low polymorphism in this three breeds.(4)The r.*464 T>C of SH2B1 gene suggested the moderate polymorphism across the four breeds. CT genotype was significantly associated with higher body weight (BW) at 56 days of age and 35-56 average daily weight gain (ADG35.56) than CC genotype in New Zealand rabbit (P<0.05); CC genotype was significantly associated with higher BW84 and ADG70-84 than TT genotype in Ira (P<0.05); TT genotype was significantly associated with higher eviscerated weight, semi-eviscerated weight than CC genotype (P<0.05), CC genotype was significantly associated with higher intramuscular fat content of longissimus lumborum than TT genotype (P<005) in Champagne. These showed that the association of r.*464 T>C of SH2B1 gene and production traits was breed specific and adverse effection between carcass traits and meat quality, genotype TT with higher carcass traits and genotype CC with higher meat quality traits in Champagne rabbit, the results also showed the contradiction between carcass traits and meat quality traits.Genotypes AA and GA of TBC1D1 gene had higher BW35 than genotype GG (P < 0.01) in NEW. Genotype GA had higher BW56 and 35-56 average daily weight gain (ADG35-56) than genotype GG (P< 0.05) in EWR. These results implied that the allele A of c.214G>A of TBC1D1 gene might had a positive effect on the trait of BW35/BW56 in two breeds.(5) Along with the days of age increasing, the mRNA relative expression of SH2B1 gene was gradually increased in skeletal muscle tissues, and the mRNA relative expression of SH2B1 gene of 70 days of age was significantly higher than 56 days of age (P<0.05) and 35 days of age (P<0.01). These showed that the mRNA relative expression of SH2B1 gene was time specificity and closely related to the growth in rabbit.(6) The different genotype’s mRNA relative expression of SH2B1 r.*464 T>C was not reached statistical significance in three period (P>0.05), that showed there was not significant association between polymorphism of SH2B1 r.*464 T>C and SH2B1 mRNA relative expression.The present study revealed that the r.*464 T>C of SH2B1 gene and c.214G>A of TBC1D1 gene should be considered as important gene markers associated with growth rates, carcass traits and meat quality traits in rabbit. |
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