雞形目是一個在世界范圍里廣布的種類,。雉科在該目里成員最多，關(guān)系最復(fù)雜,。中國擁有世界上雉科近1/3的種類,，其中又有大約1/3是我國的特產(chǎn)種，有“雉類的王國”之稱,。該目包含了人們所熟悉以及有重要經(jīng)濟(jì)價值的家雞,，火雞，鵪鶉等,；也包含了很多稀有的觀賞鳥類,，比如紅腹錦雞，紅腹角雉,，白鷴等,。由于它們具有重要的科學(xué)與經(jīng)濟(jì)價值，雞形目的研究倍受關(guān)注,。然而到目前為止,，它們的系統(tǒng)發(fā)育關(guān)系仍然混淆不清，很多研究得出互相矛盾的結(jié)果,，尤其是雉科物種的系統(tǒng)發(fā)育關(guān)系十分復(fù)雜,。
在昆明動物研究所張亞平院士的帶領(lǐng)下，博士生沈永義與本所楊曉君課題組以及四川大學(xué)岳碧松教授合作,，分析了雞形目34個種的線粒體全基因組,，得到了支持率較高的系統(tǒng)樹，為澄清雞形目,，特別是雉科長期混淆不清的系統(tǒng)發(fā)育關(guān)系提供了重要的證據(jù),。他們的結(jié)果提示，傳統(tǒng)上根據(jù)形態(tài)等劃分的雉類,、鶉類,、孔雀類以及角雉類可能都不是單系，也就是說雉科形態(tài)發(fā)生了多次的趨同進(jìn)化,，導(dǎo)致了依賴外形的傳統(tǒng)分類的困難,。而之前根據(jù)單個基因或者少數(shù)幾個基因的研究，各個節(jié)點支持率很低,，留下很多頗有爭議的系統(tǒng)發(fā)育關(guān)系,。
這些問題在本研究中得到較好的解決,，說明線粒體全基因組分析是解決這種快速輻射進(jìn)化類群系統(tǒng)發(fā)育關(guān)系的有效途徑。他們的結(jié)果為進(jìn)一步研究雉科的輻射分化,、雌雄二色性和飛行能力的多次獨立退化等提供了很好的基礎(chǔ),。該研究發(fā)表近期在國際著名雜志BMC Evolutionary Biology 上。(生物谷Bioon.com)
生物谷推薦原文出處：
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.
