Genetic Polymorphisms Of H-FABP And ADD1 Gene And The Association With Intramuscular Fat Content In Tan Sheep

Five populations altogether of 264 sheep samples including Tan sheep, Small-Tailed Han Sheep, Tan×SH F1, Suffolk and Poll Dorset sheep were selected , of which the difference of their slaughter and meat quality physicochemical properties were studied between Tan sheep and Tan×Han F1. Meanwhile, the polymorphisms, genetic variation of H-FABP gene and ADD1 gene, tissues expression and the associations with IMF were detected by PCR-SSCP, DNA sequencing and RT-PCR, exploring further its possible associations with IMF traits in sheep, in order to offer foundation for the MAS of meat quality in sheep.The analysed results showed that: the body weight, corpus weight, backfat thickness,GR value and intramuscular fat(IMF) content were improved, but the water loss rate was increased, simultaneously tenderness,and rate of cooked meat were lowered with the ages going on, which was not conducive to the quality of meat. Meanwhile, the properties of Tan sheep such as the body weight, corpus weight, slaughter rate and so on were improved after crossbreeded with Small-Tail Han sheep. Especialy, the Tan sheep had significant(P<0.05) and more significant differences (P<0.01) on tenderness, meat colour, cooked meat rate and IMF content than that of THF1. What we got may offer some objective data for meat quality properties of Tan sheep.By PCR-SSCP and DNA sequencing, ten pairs of PCR primers were designed to amplify and screen exon 2 to exon4 and 3′UTR regions of H-FABP gene. As a result, four pairs of primers of SSCP analysis showed polymorphisms, and 10 alleles were identified. 8 single base mutations were found in H-FABP gene of sheep for the first time, and all of them were in introns. The genetic polymorphisms informations showed that: the polymorphism information contents (PIC ) were low or moderate level from 0 to 0.5136. The association of polymorphisms sites of H-FABP gene with IMF content by GLM procedure of SAS indicated that:The LSM±SE of genotype AA had more significant differences (P<0.01) than that of BB in primer P2 site, and it was the same as genotype HH and Hh in primer P4 site, moreover, the LSM±SE of adult sheep were superior to(P<0.05)that of young sheep with the same genotypes.Seven pairs of PCR primers were designed covering with exons 2-8 regions of ADD1 gene to detected by PCR-SSCP, and 1 polymorphism site along with 3 alleles were identified. 4 single base mutations were screened by DNA sequencing in ADD1 gene, of which 1 was in exon 5, others were in intron 5 without leading to amino acid substitutions.The PIC were in low level (PIC<0.25). The LSM±SE of IMF content of genotype AA was more than that of BB in adults, and it was the same as genotype AA and AB in young sheep, but there was no significant difference (P>0.05) in all of them. The fluorescence real-time PCR was used to evaluate the different tissues expression of H-FABP gene in Tan sheep. The result showed that it had the high expression in heart and skelecton muscle, and the low expression in the other tissues, of which the heart muscle expression was the most and the lung was the little.