美日兩國(guó)科學(xué)家近日在棘魚（stickleback fish）身上的實(shí)驗(yàn)首次顯示，新的性染色體的進(jìn)化驅(qū)動(dòng)了脊椎動(dòng)物新種的形成,。相關(guān)研究成果9月27日在線發(fā)表于《自然》雜志,。
直至目前，多數(shù)證據(jù)顯示新物種的產(chǎn)生是因適應(yīng)環(huán)境而致,。但日本東北大學(xué)進(jìn)化生物學(xué)家Jun Kitano領(lǐng)導(dǎo)研究小組發(fā)現(xiàn),，日本海棘魚擁有著與其祖先不同的性染色體，其祖先的Y染色體與一個(gè)常染色體融合,，創(chuàng)造出了一個(gè)新的性染色體,。
研究小組還觀察到，雄性日本海棘魚比其祖先表現(xiàn)出更多的攻擊性交配行為,，使得進(jìn)化自祖先群體的雌性避免與它們交配,。而且在實(shí)驗(yàn)室測(cè)試中，這兩種群體交配產(chǎn)生的后代是不育的,。
研究小組發(fā)現(xiàn),，造成雄性日本海棘魚攻擊性交配行為的基因位于這一新的Y染色體上。這種交配行為阻止了兩種群體進(jìn)行交配,，使得日本海棘魚成為了一個(gè)新種,。
瑞士聯(lián)邦水生科技研究所魚類生態(tài)學(xué)家和進(jìn)化學(xué)家Ole Seehausen表示，這一研究是“非凡的”,，“這是首次研究顯示,，脊椎動(dòng)物性染色體進(jìn)化與新種進(jìn)化之間存在直接聯(lián)系”,。
不過該研究并沒有回答，兩性間的沖突是否驅(qū)動(dòng)了新性染色體的進(jìn)化,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 27 September 2009 | doi:10.1038/nature08441
A role for a neo-sex chromosome in stickleback speciation
Jun Kitano1,7, Joseph A. Ross1,2,7, Seiichi Mori3, Manabu Kume4, Felicity C. Jones5, Yingguang F. Chan5, Devin M. Absher6,7, Jane Grimwood6,7, Jeremy Schmutz6,7, Richard M. Myers6,7, David M. Kingsley5 & Catherine L. Peichel1
1 Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, Washington 98109, USA
2 Graduate Program in Molecular and Cellular Biology, University of Washington, Seattle, Washington 98195, USA
3 Biological Laboratory, Gifu-keizai University, Ogaki, Gifu 503-8550, Japan
4 Aqua Restoration Research Center, Public Works Research Institute, Kakamigahara, Gifu 501-6021, Japan
5 Department of Developmental Biology and Howard Hughes Medical Institute, Stanford University, Stanford, California 94305, USA
6 Department of Genetics and Stanford Human Genome Center, Stanford University, Stanford, California 94304, USA
7 Present addresses: Department of Ecology and Evolutionary Biology, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan (J.K.); Department of Biology, University of Maryland, College Park, Maryland 20742, USA (J.A.R.); HudsonAlpha Institute for Biotechnology, Huntsville, Alabama 35806, USA (D.M.A., J.G., J.S. and R.M.M.)
Correspondence to: Catherine L. Peichel1 Correspondence and requests for materials should be addressed to C.L.P.
Sexual antagonism, or conflict between the sexes, has been proposed as a driving force in both sex-chromosome turnover and speciation. Although closely related species often have different sex-chromosome systems, it is unknown whether sex-chromosome turnover contributes to the evolution of reproductive isolation between species. Here we show that a newly evolved sex chromosome contains genes that contribute to speciation in threespine stickleback fish (Gasterosteus aculeatus). We first identified a neo-sex chromosome system found only in one member of a sympatric species pair in Japan. We then performed genetic linkage mapping of male-specific traits important for reproductive isolation between the Japanese species pair. The neo-X chromosome contains loci for male courtship display traits that contribute to behavioural isolation, whereas the ancestral X chromosome contains loci for both behavioural isolation and hybrid male sterility. Our work not only provides strong evidence for a large X-effect on reproductive isolation in a vertebrate system, but also provides direct evidence that a young neo-X chromosome contributes to reproductive isolation between closely related species. Our data indicate that sex-chromosome turnover might have a greater role in speciation than was previously appreciated.
