生物谷：人類為何如此特殊,？美國科學(xué)家近日對比研究了人類和其它靈長類動物的基因組,，發(fā)現(xiàn)這可能是因為人類某些基因的拷貝數(shù)與其它動物有很大不同。這一發(fā)現(xiàn)將有助于人們對疾病,、壽命等展開更深入的研究。相關(guān)論文在線發(fā)表于7月31日的《基因組研究》（Genome Research）上。
美國科羅拉多大學(xué)的James Sikela等人比較了24000多種人類及黑猩猩,、大猩猩等8種靈長類動物基因中的DNA。應(yīng)用比較基因組雜交（CGH）技術(shù),，他們總共發(fā)現(xiàn)了4000多種表現(xiàn)了種系特異性變化的基因拷貝,，而且這個數(shù)量還隨著進(jìn)化不斷增長。比較起來,，人類比其它靈長動物的這種基因要少得多——人類只有84種這種基因,，而狐猴則有1180種。
這些具有多個拷貝的基因往往具有很特殊的作用,。比如其中一個名為aquaporin 7的基因,，人類具有它的五個拷貝，而其它靈長類動物只有兩個,。研究人員推測,，這個基因可能與人類特有的運(yùn)動性出汗及耐力跑有關(guān)。
研究人員還確定了染色體中一些基因復(fù)制和基因損失特別活躍的區(qū)域,。Sikela表示,，這些復(fù)制和損失是一把雙刃劍，它能為進(jìn)化提供多種可供選擇的變異,，但也很容易導(dǎo)致疾病,，比如能夠擴(kuò)大大猩猩食譜的基因會使人類患上易導(dǎo)致心臟病的DiGeorge綜合癥,。
美國加州大學(xué)圣地亞哥分校的Ajit Varki表示，此次的研究使我們認(rèn)識到,，人類和其它靈長動物基因組之間的差別比我們想象得要復(fù)雜的多,。此次的研究只是個開始，更明確的結(jié)果則有待于更深入的研究,。（科學(xué)網(wǎng) 梅進(jìn)/編譯）
原始出處:
Published online before print July 31, 2007
Genome Research, DOI: 10.1101/gr.6557307
Gene copy number variation spanning 60 million years of human and primate evolution
Laura Dumas1, Young H. Kim2, Anis Karimpour-Fard3, Michael Cox1,4,5, Janet Hopkins1,4,5, Jonathan R. Pollack2, and James M. Sikela1,4,5,6
1 Human Medical Genetics Program, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado 80045, USA; 2 Department of Pathology, Stanford University, Stanford, California 94305, USA; 3 Department of Preventative Medicine and Biometrics, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado 80045, USA; 4 Neuroscience Program, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado 80045, USA; 5 Department of Pharmacology, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado 80045, USA
Given the evolutionary importance of gene duplication to the emergence of species-specific traits, we have extended the application of cDNA array-based comparative genomic hybridization (aCGH) to survey gene duplications and losses genome-wide across 10 primate species, including human. Using human cDNA arrays that contained 41,126 cDNAs, corresponding to 24,473 unique human genes, we identified 4159 genes that likely represent most of the major lineage-specific gene copy number gains and losses that have occurred in these species over the past 60 million years. We analyzed 1,233,780 gene-to-gene data points and found that gene gains typically outnumbered losses (ratio of gains/losses = 2.34) and these frequently cluster in complex and dynamic genomic regions that are likely to serve as gene nurseries. Almost one-third of all human genes (6696) exhibit an aCGH- predicted change in copy number in one or more of these species, and within-species gene amplification is also evident. Many of the genes identified here are likely to be important to lineage-specific traits including, for example, human-specific duplications of the AQP7 gene, which represent intriguing candidates to underlie the key physiological adaptations in thermoregulation and energy utilization that permitted human endurance running.
6 Corresponding author.
E-mail [email protected] ; fax: (303) 724-3663.
