2012年8月25日 訊 /生物谷BIOON/ --黑猩猩與人類有百分之九十六個基因組是相同的,。而這4％的巨大差異引起了佐治亞理工學(xué)院的Soojin Yi的興趣。例如,，為什么人類具有較高的患癌風(fēng)險,，而黑猩猩很少患這種疾病,？
在9月的American Journal of Human Genetic雜志上發(fā)表的一項研究中,，Yi分析了每一個物種的腦組織樣本。她發(fā)現(xiàn)某些DNA修飾（也稱為甲基化）的差異性可能會導(dǎo)致表型的改變,。結(jié)果還提示,，DNA甲基化對于某些人類疾病相關(guān)的表型包括癌癥和孤獨癥中起著重要的作用，Yi說：我們的研究表明,，某些人類疾病可能是進(jìn)化后生起源的,，這樣的研究結(jié)果從長遠(yuǎn)來看，可能有助于更好的開發(fā)治療某些人類疾病的手段,。
DNA甲基化修飾基因的表達(dá),，但這一過程并不改變細(xì)胞的遺傳信息。為了了解兩個物種之間DNA甲基化有何不同,，Yi和她的研究小組描繪了多個人類個體和黑猩猩前額葉皮層的全基因組甲基化圖譜,。他們發(fā)現(xiàn)數(shù)人類大腦中百個基因的甲基化水平表現(xiàn)出顯著降低，相比較于黑猩猩大腦而言,。這些基因中的大多數(shù)都與蛋白結(jié)合以及細(xì)胞代謝過程中有關(guān),。
Yi說：這些基因與自閉癥,、神經(jīng)管缺陷、酒精和其他化學(xué)品的依賴相關(guān),。這表明物種之間的甲基化差異可能產(chǎn)生顯著的功能性后果,。這些基因甲基化的差異還可能與某些疾病包括癌癥等有關(guān)。該項研究由佐治亞理工學(xué)院研究和教育項目（GT-FIRE）和美國國家科學(xué)基金會獎助金（MCB-0950896 BCS-0751481）創(chuàng)新基金資助,。（生物谷：Bioon.com）
編譯自：Human-Chimp Genetic Differences: New Insights Into Why Humans Are More Susceptible to Cancer and Other Diseases
doi:10.1016/j.ajhg.2012.07.024
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Divergent Whole-Genome Methylation Maps of Human and Chimpanzee Brains Reveal Epigenetic Basis of Human Regulatory Evolution.
Jia Zeng, Genevieve Konopka, Brendan G. Hunt, Todd M. Preuss, Dan Geschwind, Soojin V. Yi.
DNA methylation is a pervasive epigenetic DNA modification that strongly affects chromatin regulation and gene expression. To date, it remains largely unknown how patterns of DNA methylation differ between closely related species and whether such differences contribute to species-specific phenotypes. To investigate these questions, we generated nucleotide-resolution whole-genome methylation maps of the prefrontal cortex of multiple humans and chimpanzees. Levels and patterns of DNA methylation vary across individuals within species according to the age and the sex of the individuals. We also found extensive species-level divergence in patterns of DNA methylation and that hundreds of genes exhibit significantly lower levels of promoter methylation in the human brain than in the chimpanzee brain. Furthermore, we investigated the functional consequences of methylation differences in humans and chimpanzees by integrating data on gene expression generated with next-generation sequencing methods, and we found a strong relationship between differential methylation and gene expression. Finally, we found that differentially methylated genes are strikingly enriched with loci associated with neurological disorders, psychological disorders, and cancers. Our results demonstrate that differential DNA methylation might be an important molecular mechanism driving gene-expression divergence between human and chimpanzee brains and might potentially contribute to the evolution of disease vulnerabilities. Thus, comparative studies of humans and chimpanzees stand to identify key epigenomic modifications underlying the evolution of human-specific traits.
