Cloning, SNPs Detection Of LPL,HSL Genes And Association Analysis Between Polymorphism And Meat Quality Traits In Cattle

Lipoprotein lipase (LPL) and Hormone-sensitive Lipase (HSL) are both key enzymes for the metabolism of circulating triacylglycerols. LPL gene and HSL gene are considered to be major candidate genes affecting meat quality traits.292 blood samples from 8 cattle breeds-Angus, Hereford, Charolais, Chinese Simmental, Qinchuan cattle, Luxi cattle, Jinnan cattle and Simmental x Mongolia were collected to extract DNA, and some adipose tissue samples from Angus were took to extract total RNA in this study. Then isolation, identification and sequences analysis of CDS sequences of bovine LPL, HSL genes were performed by homologous cloning and bioinformatics methods combined with RT-PCR, electronic-PCR and so on. Lipoprotein lipase and hormone-sensitive lipase are the key enzymes responsible for fat deposition and fat mobilization in white adipose tissue. PCR-RFLP, PCR-SSCP and sequencing method were employed to detect SNPs in some genomic fragments of the two genes. Association analysis between LPL, HSL gene polymorphisms and some beef quality traits in 8 populations was studyed. The main results were as follows:1. Using RT-PCR method, the complete CDS sequences of LPL,HSL gene were cloned and identified from adipose tissue. The amino acids were been deduced and the motifs were predicted. Results showed that the LPL protein and HSL proteins were composed of 478 and 756 amino acids respectively.2. PCR-SSCP mothed was used to detect polymorphisms of Exon1-9,Intron1 of LPL gene and Exon 7,8 of HSL gene, polymorphisms in Exon2(A65T), 5(A182G), 6(T31C), 8(G12A), 9(T/C, C/G, T/C, C/T)and Intron1(TTTGT deletion mutation) were detected.3. According to statistical analysis of data of heterozygosities (H), effective number of alleles (Ne), polymorphism information contents (PIC), the polymorphism infonnation contents were moderate polymorphisms (0.250.05) except Simmental×Mongolia in Intron1.4. PCR-RFLP method was used to study the polymorphism of Exon2 Hinf I-RFLP and Exon5 Msp I -RFLP, The analysis of general lineal model was employed to analyse association between the SNPs and some meat quality traits. Results showed that a significant difference was found of Loin-musle area between BB genotype and AB, AA genotypes in LPL-Exon2 Hinf I-RFLP (P<0.05). A significant difference was found of backfat thickness between BB genotype and AB,AA genotypes in Exon5 Msp I -RFLP(P<0.05). No significant difference of other meat quality traits between different genotypes was found (P>0.05).