Study On Relationship Between Polymorphism Of DGAT1, DGAT2 Genes And Milk Production Traitsin In Xinong Saanen Dairy Goat

In this experiment, the genetic polymorphism of sixteen sites of DGAT1 gene, DGAT2 gene and LOX-1 gene were analyzed through PCR-SSCP and DNA sequencing techniques in Xinong Saanen dairy goat, and analysis the association between genetic variations and milk production traits. The aim was to find out the DNA marker related to milk production trait, this markers can provide theoretical base for breeding in dairy goat. The results were in the followings:1. The association between genetic polymorphism of 5' regulated region of DGAT1 gene and milk production traitsThere were three kinds of genotypes, i.e. AA, AG and GG of the 5'UTR regulated region of DGAT1 gene were found and their genotype frequencies were 0.3655,0.5431,0.0914 respectively. The sequencing results showed that compared with the genotype AA, genotype GG had two mutations with the position 154bp (A>G) and 206bp (G>C) of the target products. The population was at Hardy-Weinberg unbalance(P<0.05). There was significant association between different genotypes in milk yield and milk fat percentage (P<0.05). Milk yield and milk fat percentage in goats with genotypies AA was significant higher than that in AG and GG genotypes(P<0.05), The result suggested that 5' regulated region of DGAT1 gene has some effect on milk production traits.2. The association between genetic polymorphism of Intron 15 locus of DGAT1 gene and milk production traitsThere were two kinds of genotypes CC and CT of the Intron 15 locus of DGAT1 gene were found and their genetype frequencies were 0.7563 and 0.2437. The sequencing results showed that compared with the genotype CC, genotype CT had one mutations with the position 299bp(C>G) of the target products. The population was at Hardy-Weinberg balance(P>0.05), there was significant association between different genotypes and milk fat percentage (P<0.05).3. The association between genetic polymorphism of exon 4 locus of DGAT2 gene and milk production traitsThere were three kinds of genotypes, i.e. AA, AT and TT of the exon 4 locus of DGAT2 gene were found and their genotype frequencies were 0.4721,0.3604,0.1675 respectively. The sequencing results showed that compared with the genotype AA, genotype TT had three mutations with the position 75bp(A>T), a deletion (C) of the 107bp, 277bp (C>A) of the target products. The population was at Hardy-Weinberg unbalance (P<0.05), there was significant association between different genotypes and milk fat percentage (P<0.05), milk fat percentage in goats with genotypies AA was significant higher than that in AT and TT genotypes(P<0.05).4. The association between genetic polymorphism of Intron 5 locus of DGAT2 gene and milk production traitsThere were three kinds of genotypes, i.e. AA, AB and BB of the Intron 5 locus of DGAT2 gene were found and their genotype frequencies were 0.2284,0.4061,0.3655 respectively. The sequencing results showed that compared with the genotype AA, genotype BB had two mutations with the position 113bp ( A>G) and 182bp (C>T) of the target products. The population was at Hardy-Weinberg balance(P>0.05), There was significant association between different genotypes in milk yield and milk fat percentage (P<0.05), Milk yield and milk fat percentage in goats with genotypies AA and AB was significant higher than that in BB genotypes(P<0.05). The result suggested that Intron 5 locus has some effect on milk yield and milk fat percentage.5. The association between genetic polymorphism of Intron 6(P1) locus of DGAT2 gene and milk production traitsThere were three kinds of genotypes, i.e. CC, CD and DD of the Intron 6(P1) locus of DGAT2 gene were found and their genotype frequencies were 0.4975,0.3553,0.1472 respectively. The sequencing results showed that compared with the genotype CC, genotype DD had one mutations with the position 170bp (C>T) of the target products. The population was at Hardy-Weinberg unbalance(P<0.05), there was significant association between different genotypes and milk fat percentage (P<0.05).6. The association between genetic polymorphism of Intron 6(P2) locus of DGAT2 gene and milk production traitsThere were two kinds of genotypes EE and EF of the Intron 6(P2) locus of DGAT2 gene were found and their genotype frequencies were 0.7005 and 0.2995. The sequencing results showed that compared with the genotype EE, genotype EF had one mutations with the position 204bp (T>G) of the target products. The population was at Hardy-Weinberg unbalance(P<0.05), Milk yield in goats with genotypies EE was significant higher than that in EF genotypes(P<0.05).