Biomedical subjects

Xue-Qin Lei

Publications and source records attributed to Xue-Qin Lei.

3 recordsLinked to original sources

PubMed2005

[Study on mitochondrial DNA D-loop polymorphism in Chinese donkeys].

The mitochondrial DNA (mtDNA) D-loop sequences with 399 bp in 26 individuals from 5 donkey breeds in China were analyzed. Aligned by Clustal W software,the results showed that 23 polymorphic nucleotide sites and only transition with the percentage of 5.76% in 399 bp were observed. In reference to mtDNA D-loop sequences of European domestic donkey as a control, the average percentage of mtDNA D-loop nucleotide variation in 5 Chinese donkey breeds was 1.80%. The average percentages of D-loop nucleotide variation from Liangzhou donkey (LZ), Yunnan donkey (YN), Guanzhong donkey (GZ), Xinjiang donkey (XJ) and Jiami donkey (JM) were 0. 35%, 1.25%, 2.30%, 2.91% and 2.20% respectively. The average sequence divergence estimated from D-loop sequences varied from 0.25% - 5.01% within breeds and 4.51% - 5.51% among breeds, respectively, demonstrating that there existed rather abundant mitochondrial genetic diversity in Chinese donkeys. Comparisons of the 26 sequences revealed 11 mitochondrial haplotypes; the percentage of haplotype was 42.31%. This phenomenon demonstrated that the mitochondrial genetic diversity in Chinese donkey breeds is being reduced. It is urgent to protect the genetic resources of Chinese donkey. The molecular phylogenetic tree of mtDNA D-loop sequences in 5 Chinese donkey breeds,6 sequences of Asian wild ass (Equus asinus kiang, Equus asinus kulan, Equus asinus hemionus;) and 4 sequences of European domestic donkeys from GenBank was constructed by Neighbor-Joining method. It was the first time proved in molecular level that the origin of Chinese donkey breeds was from African wild ass (Equus africanus africanus and Equus africanus somaliensis), not from Asian wild ass as bescribed in the paper.

Animals↗

PubMed2004

[Study on mitochondrial DNA genetic diversity of some cattle breeds in China].

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.

Animals↗

PubMed2003

[Polymorphisms of insulin-like growth factor binding protein 3 gene and its associations with several carcass traits in Qinchuan cattle].

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).

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