Kanginakudru Sriramana, Metta Muralidhar, Jakati R D, Nagaraju J
Laboratory of Molecular Genetics, Centre for DNA Fingerprinting and Diagnostics, ECIL-Road, Nacaharam, Hyderabad, 500076, India.
BMC Evol Biol. 2008 Jun 10;8:174. doi: 10.1186/1471-2148-8-174.
Domestication of chicken is believed to have occurred in Southeast Asia, especially in Indus valley. However, non-inclusion of Indian red jungle fowl (RJF), Gallus gallus murghi in previous studies has left a big gap in understanding the relationship of this major group of birds. In the present study, we addressed this issue by analyzing 76 Indian birds that included 56 G. g. murghi (RJF), 16 G. g. domesticus (domestic chicken) and 4 G. sonneratii (Grey JF) using both microsatellite markers and mitochondrial D-loop sequences. We also compared the D-loop sequences of Indian birds with those of 779 birds obtained from GenBank.
Microsatellite marker analyses of Indian birds indicated an average FST of 0.126 within G. g. murghi, and 0.154 within G. g. domesticus while it was more than 0.2 between the two groups. The microsatellite-based phylogenetic trees showed a clear separation of G. g. domesticus from G. g. murghi, and G. sonneratii. Mitochondrial DNA based mismatch distribution analyses showed a lower Harpending's raggedness index in both G. g. murghi (0.001515) and in Indian G. g. domesticus (0.0149) birds indicating population expansion. When meta analysis of global populations of 855 birds was carried out using median joining haplotype network, 43 Indian birds of G. g. domesticus (19 haplotypes) were distributed throughout the network sharing haplotypes with the RJFs of different origins.
Our results suggest that the domestication of chicken has occurred independently in different locations of Asia including India. We found evidence for domestication of Indian birds from G. g. spadiceus and G. g. gallus as well as from G. g. murghi, corroborating multiple domestication of Indian and other domestic chicken. In contrast to the commonly held view that RJF and domestic birds hybridize in nature, the present study shows that G. g. murghi is relatively pure. Further, the study also suggested that the chicken populations have undergone population expansion, especially in the Indus valley.
人们认为鸡的驯化发生在东南亚，尤其是印度河流域。然而，此前的研究未纳入印度红原鸡（RJF），即红色原鸡指名亚种（Gallus gallus murghi），这在理解这一主要鸟类群体的关系方面留下了很大空白。在本研究中，我们通过使用微卫星标记和线粒体D-loop序列分析76只印度鸟类来解决这一问题，这些鸟类包括56只红色原鸡指名亚种（RJF）、16只家鸡（G. g. domesticus）和4只灰原鸡（G. sonneratii）。我们还将印度鸟类的D-loop序列与从GenBank获得的779只鸟类的序列进行了比较。
对印度鸟类的微卫星标记分析表明，红色原鸡指名亚种内的平均FST为0.126，家鸡内的平均FST为0.154，而两组之间的FST超过0.2。基于微卫星的系统发育树显示家鸡与红色原鸡指名亚种以及灰原鸡明显分离。基于线粒体DNA的错配分布分析表明，红色原鸡指名亚种（0.001515）和印度家鸡（0.0149）的哈彭丁参差不齐指数较低，表明种群扩张。当使用中位数连接单倍型网络对855只鸟类的全球种群进行荟萃分析时，43只印度家鸡（19个单倍型）分布在整个网络中，与不同来源的红色原鸡共享单倍型。
我们的结果表明，鸡的驯化在包括印度在内的亚洲不同地区独立发生。我们发现了印度鸟类从灰纹原鸡（G. g. spadiceus）、原鸡指名亚种（G. g. gallus）以及红色原鸡指名亚种驯化而来的证据，证实了印度家鸡和其他家鸡的多次驯化。与普遍认为红色原鸡和家鸡在自然中杂交的观点相反，本研究表明红色原鸡指名亚种相对纯正。此外，该研究还表明鸡种群经历了种群扩张，尤其是在印度河流域。
