广东省地方鸡线粒体遗传多样性与母系起源

系统评估地方鸡的遗传变异水平并追溯其母系起源, 可为保护利用优质家禽种质资源库提供科学依据。本研究测定了广东省和邻省共12个地方鸡品种的线粒体DNA D-loop序列, 分析品种间的遗传距离与系统关系, 并构建单倍型系统发生树和中介网络图。360份样品共检测到60个突变位点, 均为转换。定义了85种单倍型, 归属于单倍型类群A、B、C和E, 在12个鸡品种中均有分布, 其中B是优势单倍型类群(187个, 51.94%), E次之(76个, 21.11%)。B02 和C01是优势单倍型(85个, 23.61%; 48个, 13.33%), 为12个鸡品种共有; E03位居第三(35个, 9.72%), 杏花鸡、黄郎鸡和宁都三黄鸡未见此单倍型。杏花鸡集中分布在单倍型类群B, 惠阳胡须鸡和中山沙栏鸡则主要分布在单倍型类群E; 怀乡鸡的单倍型数量最多, 中山沙栏鸡的最少。广东地方鸡品种间遗传距离为0.012-0.015, 单倍型多样性0.805 ± 0.047至0.949 ± 0.026, 核苷酸多样性0.0102 ± 0.0017至0.0138 ± 0.0009。邻接树和中介网络图将85种单倍型划分为进化枝A、B、C和E, 广东省与邻省地方鸡单倍型的地理分布模式相似。中性检验显示广东地方鸡未经历明显的群体历史扩张。结果表明广东地方鸡处于较好的保护状态, 遗传多样性水平较高, 品种的形成受到邻省和北方家鸡的影响, 东南亚红原鸡对广东地方鸡也有重要的遗传贡献。

Mitochondrial genetic diversity and maternal origin of Guangdong indigenous chickens

The evaluation of the genetic diversity of indigenous chickens and the tracing of their matrilineal origin need to be facilitated to protect and utilize the germplasm bank of quality poultry. Twelve indigenous chicken breeds from Guangdong Province and its adjacent regions were used for mitochondrial DNA (mtDNA) D-loop sequencing, and analyses of genetic distance and genetic relationship between breeds were conducted. We constructed a phylogenetic tree and median-joining network based on haplotypes. Sixty mutation sites were detected in 360 samples, and all of these were found to be in transition. Eighty-five haplotypes, belonging to haplogroups A, B, C, and E, were defined. B was the predominant haplogroup (187, 51.94%), followed by E (76, 21.11%). Haplogroups A, B, C, and E were distributed in all the 12 breeds. B02 and C01 were the predominant haplotypes (85, 23.61%; 48, 13.33%), which were shared by all twelve breeds; and E03 ranked third (35, 9.72%), and was absent in the Xinghua, Huanglang and Ningdu yellow chicken. Xinghua chickens occurred mainly in haplogroup B, while Huiyang bearded and Zhongshan shalan chickens were distributed mainly in E. The number of haplotypes of Huaixiang chicken was the largest, while the Zhongshan shalan chicken had the fewest. The genetic distance between Guangdong chicken breeds ranged from 0.012 to 0.015, with haplotype diversity and nucleotide diversity ranging from 0.805 ± 0.047 to 0.949 ± 0.026, and from 0.0102 ± 0.0017 to 0.0138 ± 0.0009, respectively. Eighty-five haplotypes were divided into clades A, B, C, and E in the phylogenetic tree and median-joining network. Similar patterns of geographical distribution of mtDNA haplotypes was found in the chicken from Guangdong Province and its adjacent regions. A neutral test indicated that Guangdong indigenous chickens have not sustained obvious population expansion. Our results suggested that Guangdong chickens have a desirable conservation status, as they carry high levels of genetic diversity, and demographic histories were influenced to some extent, by the gene flow of domestic chickens from adjacent provinces and northern China. The red junglefowls from Southeast Asia have an important genetic contribution to the indigenous chickens of Guangdong Province.