Study On Genetic Diversity And Evolution Of Xuefeng Black-boned Chicken

Xuefeng black-bone chicken is excellent in meat and drug, which lives in Xuefeng mountain in the southwest of Hunan province. This species has high medicinal value, refine meat, good taste and so on. It has important academic value and economic value for us to study the heredity performance and community structure.To discuss the Origin, evolution and hereditary diversity of Xuefeng black-bone chicken, this research has extracted the mtDNA of 95 individuals, amplified the D-loop area DNA sequences by polymerase chain reaction (PCR), sequencing and analyzing. We downloaded 56 sequences of mitochondria D-loop from GeneBank, including red gallus gallus and gallus domesticus. Analysis the sequences by MEGA version 2.1 software packet. Assessed the value of haplotype diversity , nucleotide diversity and average number of nuclediffreences by Dnasp4.0 software packe. The UPGMA and NJ trees of the mitochondria D-loop sequences of chickens were constructed with Kimura model by the MEGA software. To study evolution of these haplotypes, the median-joining networks were drawn by Network 4.0 software.Our main results were summarized as follows:1 .It is the first time to obtain the11 gene sequences of mitochondria D-loop DNA of Xuefeng black-bone chicken. These sequneces were accepted by GeneBank of National Center for Biotechnology Information,the GeneBank accession numbers were EU598205,EU598206,EU598207,EU598208,EU598209,EU598210,EU598211,EU598212,EU598213,EU598214,EU598215 respectively.2. The length of 539 bp sequences exist 13 haplotype. Compared with the standard sequence (Genbank No. NC001323), we also observed 25 informative polymorphic sites and all the sites only occurred transversion, no conversion, no missing and insert variation, the average exchange rate for the top is 4.638 percent (25/539).3.Haplotype H1, H3 and H5 was the major haplotype in the 23 haplotype of Xuefeng black- bone chicken and others. But Xuefeng black- bone chicken had seven unique haplotypes (H11-14, H19-21). 4. The haplotypes diversity and ribonucleotides diversity were 0.9750 and 0.0136, respectively. The differences of ribonucleotides was 7.325. These results indicated that the Xuefeng black bone chicken has a high level of genetic diversity.5.According to the genetic distance of the sequences, we constructed NJ evolutionary tree by MEGA software and discovered the 13 haplotype was divided into four evolutionary direction. This means that Xuefeng black-bone chicken have four maternal lineages.6.Xuefeng black-bone chicken,Yan Jin black- bone chicken and Yu Gan black-bone chicken had closer genetic relationship. They had closer genetic relationship with red jungle fowl than others.7.Xuefeng black- bone chicken ,Yan Jin black- bone chicken and Yu Gan black- bone chicken perhaps came from Red Jungle Fowl-Thailand, Red Jungle Fowl-Laos and Red Jungle Fowl-Vietnam. They had gene flowed with the other Chinese domestic chicken breeds.