Study On The Molecular Evolution And Phylogeny Of Mitochondrial D-loop Sequence Polymorphic In Duck

This study sequenced the mitochondrial DNA control region partial sequence of 106 individuals from four different domestic duck breeds or strains in Zhejiang province, one Xihu Mallard and Muscovy duck were also included in this analysis. The results showed:The partial sequence of mtDNA D-loop of four domestic duck was 523 bp, and T,C,A,G content were 25.1%,35.0%,23.5%,16.5%,respectively. 12 sites were polymorphic (2.29% in 523) with 8 singleton polymorphic sites (1.53%) and 4 parsimony informative polymorphic sites (0.76%). There were two types of mutation of nucleotide including insertion/deletion. They were transition and transversion. There were 10 times of transition (83.3% in 12) and 1 time of transfusion (16.7% in 12). Average nucleotide diversity of breeds respectively were 0.408%,0.193%,0.098%,0.372%. This indicted that the nucleotide diversity of breeds was not plentiful. This research defined 12 haplotypes, and average haplotypes diversity was 0.769±0.035. It suggested the types of haplotypes were abundant. In total, the genetic diversity was poor in Zhejiang duck.This research determined the mitochondrial DNA control region partial sequence of 31 individuals from Xihu Mallard, and found 4 haplotypes.The average haplotypes diversity was 0.424±0.095 and nucleotide diversity was 0.004784±0.00342. It showed the haplotypes diversity and nucleotide diversity was poor. Pooled with published data in gene bank of Anas platyrhynchos D-loop part sequence haplotypes, we calculated the Kimura 2-parameter distance between Xihu Mallard and Anas platyrhynchos. The distance between domestic duck and Arias platyrhynchos (B haplotype) was 0.032±0.007; and the distance between domestic duck and Xihu Mallard was 0.004±0.007. Using software Paup4.0 and Mega2.1 to construct N J-tree of D-loop partial sequence of duck, the results show that those haplotypes were clustered two different clades A and B. 16 haplotypes were found in our research from Xihu Mallard and domestic duck were clustered in clade A. It indicated that the genesis of domestic duck was unity.The partial sequence of mtDNA D-loop of Muscovy duck was sequenced too, and T,C,A,G content were24. 3%,33.5%,25.1%,17.1%, respectively. We detected 547 sites were polymorphic and 6 haplotypes. It indicated the haplotypes diversity was plentiful, but the nucleotide diversity was poor. Pooled with published data in gene bank of Anas platyrhynchos D-loop partial sequence haplotypes, we calculated the Kimura 2-parameter distance and construct N J-tree. The result showed that the distance between Muscovy duck and Aix galericulata,Anas platyrhynchos,Netta rufina were 0.089±0.013,0. 095±0.013,0.111±0.016 respectively. From the NJ-tree, we can see that the Muscovy duck was together with Aix galericulata firstly, and then together with Netta rufina. According to the distance, we can conclude that Muscovy duck was closed to Aix galericulata.