英國(guó)科學(xué)家在The American Journal of Human Genetics上發(fā)表最新文章,，發(fā)現(xiàn)人類(lèi)的基因中每200個(gè)基因中有1個(gè)基因是多余的,！
該研究論文的通訊作者是Chris Tyler-Smith，Chris研究小組從整個(gè)基因組的水平分析基因的無(wú)意義的單核甘酸突變給基因帶來(lái)的影響,，研究發(fā)現(xiàn),，在終止密碼子中無(wú)意義單核甘酸的突變可能導(dǎo)致基因無(wú)法表達(dá)目的蛋白或是表達(dá)功能不全的蛋白甚至是有害的蛋白產(chǎn)物。
研究小組從全世界范圍內(nèi)研究了上1000人的遺傳密碼子,，研究關(guān)注的焦點(diǎn)是單個(gè)堿基的變化（單個(gè)核苷酸的變化）,，尤其是這些變化對(duì)蛋白表達(dá)所造成的影響是關(guān)注的焦點(diǎn)。研究者將這些變化稱(chēng)為無(wú)意義SNP（nonsense SNP）,，這些無(wú)意義的突變也許對(duì)人體造成不利的影響,。
研究者稱(chēng)，這些變化也許與人類(lèi)的某些遺傳疾病有密切的關(guān)系,，但是令人驚訝的是,，這種無(wú)意義的突變?cè)谄胀ǖ娜巳褐泻芷毡椤Ｆ骄總€(gè)人發(fā)生這樣的突變約有46次,。
人類(lèi)基因組包含有約20,000個(gè)基因,，其中有99個(gè)基因發(fā)生SNP突變，意味著在每200個(gè)基因中至少有1個(gè)基因變成多余的無(wú)意義的,；而另外的一些無(wú)意義SNP突變發(fā)生在167個(gè)基因中,，其中有8個(gè)突變數(shù)據(jù)出現(xiàn)在人類(lèi)基因突變數(shù)據(jù)中，這8個(gè)突變與遺傳疾病有關(guān)聯(lián),。
研究者發(fā)現(xiàn)有些基因的丟失對(duì)人類(lèi)的健康和進(jìn)化沒(méi)有影響,，比如說(shuō)，在亞洲,，丟失MAGEE2基因?qū)】禌](méi)有影響,。
Chris說(shuō)，也許基因?qū)W也存在less is more的定理,。
這項(xiàng)研究為基因組學(xué)研究提出了一個(gè)新的問(wèn)題：基因的丟失對(duì)人類(lèi)健康和進(jìn)化有何影響,？（生物谷Bioon.com）
生物谷推薦原始出處：
The American Journal of Human Genetics, 05 February 2009 doi:10.1016/j.ajhg.2009.01.008
A Genome-wide Survey of the Prevalence and Evolutionary Forces Acting on Human Nonsense SNPs
Bryndis Yngvadottir1,Yali Xue1,Steve Searle1,Sarah Hunt1,Marcos Delgado1,Jonathan Morrison1,2,Pamela Whittaker1,Panos Deloukas1andChris Tyler-Smith1,,
1 The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambs CB10 1SA, UK
2 Present address: Cancer Research UK, Genetic Epidemiology Unit, Strangeways Research Laboratory, Worts Causeway, Cambridge CB1 8RN, UK
Nonsense SNPs introduce premature termination codons into genes and can result in the absence of a gene product or in a truncated and potentially harmful protein, so they are often considered disadvantageous and are associated with disease susceptibility. As such, we might expect the disrupted allele to be rare and, in healthy people, observed only in a heterozygous state. However, some, like those in the CASP12 and ACTN3 genes, are known to be present at high frequencies and to occur often in a homozygous state and seem to have been advantageous in recent human evolution. To evaluate the selective forces acting on nonsense SNPs as a class, we have carried out a large-scale experimental survey of nonsense SNPs in the human genome by genotyping 805 of them (plus control synonymous SNPs) in 1,151 individuals from 56 worldwide populations. We identified 169 genes containing nonsense SNPs that were variable in our samples, of which 99 were found with both copies inactivated in at least one individual. We found that the sampled humans differ on average by 24 genes (out of about 20,000) because of these nonsense SNPs alone. As might be expected, nonsense SNPs as a class were found to be slightly disadvantageous over evolutionary timescales, but a few nevertheless showed signs of being possibly advantageous, as indicated by unusually high levels of population differentiation, long haplotypes, and/or high frequencies of derived alleles. This study underlines the extent of variation in gene content within humans and emphasizes the importance of understanding this type of variation.
