多種生物在遷移到新的生存環(huán)境并不斷適應(yīng)的過(guò)程中會(huì)進(jìn)化出不同的色素沉積方式,。在12月14日出版的《細(xì)胞》（Cell）上，來(lái)自美國(guó),、葡萄牙和加拿大的科學(xué)家發(fā)現(xiàn),，三刺魚（threespine stickleback）體內(nèi)干細(xì)胞因子基因Kit ligand的改變與其身體顏色變化有關(guān)，三刺魚在上一次冰河期末期遷移到新的淡水環(huán)境中,。而現(xiàn)代人類在過(guò)去5萬(wàn)年間也不斷拓展生存環(huán)境,，科學(xué)家表示，Kit ligand基因同樣對(duì)不同人種的膚色進(jìn)化起到了作用,。
最近,，很多研究表明，特定的基因可能被不同生物利用,，從而進(jìn)化出類似的表型,。盡管科學(xué)家對(duì)于這種現(xiàn)象的內(nèi)在遺傳學(xué)機(jī)制很感興趣，但是很難找到合適的研究對(duì)象,。而三刺魚是一種分析脊椎動(dòng)物進(jìn)化的基因基礎(chǔ)的強(qiáng)大工具,。之前大部分針對(duì)三刺魚的基因定位研究主要針對(duì)骨骼結(jié)構(gòu)和體型，然而色素變化是進(jìn)行不同物種間比較研究的合適顯型,。
三刺魚和人類在從原始環(huán)境中遷移到新的生存環(huán)境中時(shí),，都會(huì)發(fā)生色素沉積的進(jìn)化改變。三刺魚擁有黑色,、雜色或白色的體色,，而人類的皮膚顏色與緯度相關(guān)。盡管存在多種針對(duì)魚類和人類色素變化的假設(shè),，但是其內(nèi)在的基因機(jī)制并不清楚,。
在最新的研究中,，科學(xué)家使用了全基因組定位技術(shù)分析了三刺魚色素沉積進(jìn)化的基因基礎(chǔ)，然后用混合定位方法研究了造成三刺魚這種色素變化的基因因子,，是否同樣與人類進(jìn)化過(guò)程中表現(xiàn)出的色素變化相關(guān),。
結(jié)果表明，不同生物表型的迅速變化或許擁有同樣的內(nèi)在機(jī)制,?？茖W(xué)家認(rèn)為，研究不同生物的其它形態(tài),、生理和行為差異進(jìn)化是否存在類似的基因?qū)W機(jī)制將會(huì)是一件很有趣的工作,。（科學(xué)網(wǎng) 何宏輝/編譯）
原始出處:
Cell, Vol 131, 1179-1189, 14 December 2007
Article
cis-Regulatory Changes in Kit Ligand Expression and Parallel Evolution of Pigmentation in Sticklebacks and Humans
Craig T. Miller,1 Sandra Beleza,2 Alex A. Pollen,1 Dolph Schluter,3 Rick A. Kittles,4 Mark D. Shriver,5 and David M. Kingsley1,
1 HHMI and Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
2 Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4250-400 Porto, Portugal
3 Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
4 Department of Medicine, Section of Genetic Medicine, The University of Chicago, Chicago, IL 60637, USA
5 Department of Anthropology, The Pennsylvania State University, University Park, PA 16802, USA
Corresponding author
David M. Kingsley
[email protected]
Dramatic pigmentation changes have evolved within most vertebrate groups, including fish and humans. Here we use genetic crosses in sticklebacks to investigate the parallel origin of pigmentation changes in natural populations. High-resolution mapping and expression experiments show that light gills and light ventrums map to a divergent regulatory allele of the Kit ligand (Kitlg) gene. The divergent allele reduces expression in gill and skin tissue and is shared by multiple derived freshwater populations with reduced pigmentation. In humans, Europeans and East Asians also share derived alleles at the KITLG locus. Strong signatures of selection map to regulatory regions surrounding the gene, and admixture mapping shows that the KITLG genomic region has a significant effect on human skin color. These experiments suggest that regulatory changes in Kitlg contribute to natural variation in vertebrate pigmentation, and that similar genetic mechanisms may underlie rapid evolutionary change in fish and humans.
