RESUMO
PCR-RFLP technique was applied to analyze correlation between the polymorphisms of CSN1 S2 (alpha(s2) casein), CSN3 (kappa casein) and beta-lg (beta-lactoglobulin) genes and milk performance in 69 individuals of Xinong Saanen dairy goat. The results showed that there was significant correlation between different genotypes of CSN1 S2 locus and milk yield:average milk yield of individuals with genotype FF was less than that of genotype NN (P < 0.05); the second lactation milk yield of individuals with genotype NN was over 90 kg higher than that with genotype FF (P < 0.01). This indicates that allele F of CSN1 S2 locus probably has significant negative effect on milk yield. The results of CSN3 gene digested with endonuclease Hind III cleavage showed that no significant difference of milk yield between genotype DE and genotype EE was detected in first, second, third and fourth lactation milk yield and average milk yield (P > 0.05). The results of CSN3 gene with endonuclease Taq I cleavage showed that no significant difference of milk yield among individuals with genotype TT, TC and CC was detected (P > 0.05). No polymorphism was detected in PCR products of CSN3 gene digested with endonuclease Hae III. The analysis of beta-lg gene's 5' flanking region (710 bp) by PCR-RFLP in Xinong Saanen dairy goat showed that milk yield of individuals with genotype AA was higher than that with genotype AB in second, third lactation milk yield and average milk yield (P < 0.05). The results implied that allele A of beta-lg gene's 5' flanking region is probably related to high milk yield.
Assuntos
Caseínas/genética , Cabras/genética , Lactoglobulinas/genética , Leite/química , Região 5'-Flanqueadora , Alelos , Animais , DNA/análise , DNA/genética , Eletroforese/métodos , Feminino , Genótipo , Lactação , Leite/normas , Reação em Cadeia da Polimerase , Polimorfismo GenéticoRESUMO
The complete mitochondrial D-loop sequences, 910 bp in length, in 22 individuals from 8 cattle breeds in China were analyzed. The results showed that A% + T% was about 61.65%. Comparisons of these 22 sequences revealed 66 polymorphic sites, and 5 types of mutation, transition, transversion, insertion, deletion and coexistence site of transition and transversion were observed,with the percentage of 81.82%, 6.06%, 7.57%, 3.03%, 1.52%, respectively. In reference to complete mtDNA D-loop of the European cattle as a control, eight Chinese cattle breeds were classified into 3 groups according to the average percentage of D-loop nucleotide variations. The lowest average percentage of mtDNA D-loop nucleotide variation was in Xizhen cattle, Mongolian cattle, Holstein, Qinchuan cattle with 0.37%, 0.44%, 0.52%, 0.66%, the mediate in Nanyang cattle and Jiaxian cattle with 1.91%, 2.02% and the highest in Jinnan cattle and Yueyang cattle with 4.47%, 4.73%, respectively. The average sequence divergence estimated from D-loop region within breeds and among breeds in China varied from 0.55% - 5.39% and 1.21% - 6.59%, respectively. Comparisons of these 22 sequences revealed 19 mitochondrial haplotypes, the percentage of haplotype was 86.36%, showing that abundant mitochondrial genetic diversity exists in Chinese cattle. The molecular phylogenetic tree of mtDNA D-loop of 8 Chinese cattle breeds was constructed by Neighbor-Joining method. The NJ tree indicated that these mtDNA sequences fell into 3 distinct haplotype groups, it also suggested in molecular level that there were probably 3 maternal origins, of which the main origins of Chinese cattle were from Bos taurus and Bos indicus.
Assuntos
Bovinos/genética , DNA Mitocondrial/genética , Animais , Sequência de Bases , Cruzamento , Variação Genética , Haplótipos , Dados de Sequência Molecular , Polimorfismo GenéticoRESUMO
DNA samples from 60 Qinchuan cattle (Bos taurus) were analyzed with PCR-RFLPs and sequencing for insulin-like growth factor binding protein 3 (IGFBP3) gene. Fragments of 651 bp were amplified with two primers and the products of PCR were digested with restriction endonuclease HaeIII. The produced fragments showed three genotypes, namely AA,AB and BB after electrophoresis. Frequencies of the genotype AA,AB,BB and allele A,B were 0.7,0.28,0.02,and 0.84,0.16,respectively. Sequence analysis showed that a transversion of C-->A at 299 nt resulted in loss of the cleaved site of restriction endonuclease HaeIII and produced this polymorphism. This polymorphic locus of IGFBP3 gene was at Hardy-Weinberg equilibrium (P>0.05). The genotypes of AA,AB,BB slightly affected several slaughter and carcass traits of Qinchuan cattle. Dressing percentage,net meat percentage, striplion percentage, tenderloin percentage, ribeye percentage and tender shoulder percentage were decreased with the genotypes of AA,AB and BB in Qinchuan cattle, but it was not significant (P>0.05). Average ribeye area in individuals of AA genotype was significantly higher than that in individuals of BB genotype (P<0.05), and beef fat content in individuals of genotype AB and BB was significantly higher than that in individuals of AA genotype (P<0.01).