鸡形目是一个在世界范围里广布的种类。雉科在该目里成员最多，关系最复杂。中国拥有世界上雉科近1/3的种类，其中又有大约1/3是我国的特产种，有“雉类的王国”之称。该目包含了人们所熟悉以及有重要经济价值的家鸡，火鸡，鹌鹑等；也包含了很多稀有的观赏鸟类，比如红腹锦鸡，红腹角雉，白鹇等。由于它们具有重要的科学与经济价值，鸡形目的研究倍受关注。然而到目前为止，它们的系统发育关系仍然混淆不清，很多研究得出互相矛盾的结果，尤其是雉科物种的系统发育关系十分复杂。
在昆明动物研究所张亚平院士的带领下，博士生沈永义与本所杨晓君课题组以及四川大学岳碧松教授合作，分析了鸡形目34个种的线粒体全基因组，得到了支持率较高的系统树，为澄清鸡形目，特别是雉科长期混淆不清的系统发育关系提供了重要的证据。他们的结果提示，传统上根据形态等划分的雉类、鹑类、孔雀类以及角雉类可能都不是单系，也就是说雉科形态发生了多次的趋同进化，导致了依赖外形的传统分类的困难。而之前根据单个基因或者少数几个基因的研究，各个节点支持率很低，留下很多颇有争议的系统发育关系。
这些问题在本研究中得到较好的解决，说明线粒体全基因组分析是解决这种快速辐射进化类群系统发育关系的有效途径。他们的结果为进一步研究雉科的辐射分化、雌雄二色性和飞行能力的多次独立退化等提供了很好的基础。该研究发表近期在国际著名杂志BMC Evolutionary Biology 上。
生物谷推荐原文出处：
BMC Evolutionary Biology 2010, 10:132doi:10.1186/1471-2148-10-132
A mitogenomic perspective on the ancient, rapid radiation in the Galliformes with an emphasis on the Phasianidae
Yong-Yi Shen1,2,3 , Lu Liang1,2,3 , Yan-Bo Sun1,2,3 , Bi-Song Yue4 , Xiao-Jun Yang1 , Robert W Murphy1,5 and Ya-Ping Zhang1,2
1 State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming 650223, China
2 Laboratory for Conservation and Utilization of Bio-resources, Yunnan University, Kunming 650091, China
3 Graduate School of the Chinese Academy of Sciences, Beijing 100000, China
4 Sichuan Key Laboratory of Conservation Biology on Endangered Wildlife, College of Life Science, Sichuan University, Chengdu, Sichuan 610064, China
5 Department of Natural History, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada
Background
The Galliformes is a well-known and widely distributed Order in Aves. The phylogenetic relationships of galliform birds, especially the turkeys, grouse, chickens, quails, and pheasants, have been studied intensively, likely because of their close association with humans. Despite extensive studies, convergent morphological evolution and rapid radiation have resulted in conflicting hypotheses of phylogenetic relationships. Many internal nodes have remained ambiguous.
Results
We analyzed the complete mitochondrial (mt) genomes from 34 galliform species, including 14 new mt genomes and 20 published mt genomes, and obtained a single, robust tree. Most of the internal branches were relatively short and the terminal branches long suggesting an ancient, rapid radiation. The Megapodiidae formed the sister group to all other galliforms, followed in sequence by the Cracidae, Odontophoridae and Numididae. The remaining clade included the Phasianidae, Tetraonidae and Meleagrididae. The genus Arborophila was the sister group of the remaining taxa followed by Polyplectron. This was followed by two major clades: ((((Gallus, Bambusicola) Francolinus) (Coturnix, Alectoris)) Pavo) and (((((((Chrysolophus, Phasianus) Lophura) Syrmaticus) Perdix) Pucrasia) (Meleagris, Bonasa)) ((Lophophorus, Tetraophasis) Tragopan))).
Conclusions
The traditional hypothesis of monophyletic lineages of pheasants, partridges, peafowls and tragopans was not supported in this study. Mitogenomic analyses recovered robust phylogenetic relationships and suggested that the Galliformes formed a model group for the study of morphological and behavioral evolution.
