5月28日從中科院昆明動(dòng)物所獲悉,，該所研究人員近期發(fā)現(xiàn),，導(dǎo)致人類大腦發(fā)育異常的MCPH1基因，在人類大腦進(jìn)化和智力起源中起到關(guān)鍵作用,，可能是人類大腦區(qū)別于其他非人靈長類大腦的重要遺傳因素之一,。相關(guān)成果在線發(fā)表于《BMC生物學(xué)》雜志。
據(jù)該所研究員宿兵介紹,，人類區(qū)別于非人靈長類最顯著的特征就是大容量的大腦和高度發(fā)達(dá)的認(rèn)知能力,。但人們?nèi)狈`長類在進(jìn)化過程中腦容量擴(kuò)增遺傳學(xué)機(jī)制的認(rèn)識(shí)和理解。
“研究該問題的一個(gè)有效手段是尋找那些突變后會(huì)導(dǎo)致人類大腦發(fā)育異常的基因,。MCPH1基因是最早被發(fā)現(xiàn)導(dǎo)致人類神經(jīng)系統(tǒng)發(fā)育異常而引起遺傳性小頭癥的基因,。”助理研究員石磊說。
通過對MCPH1基因的蛋白序列比較分析,，科研人員鑒定了一組人類和大猿特異的氨基酸突變,，并對這些突變位點(diǎn)的功能效應(yīng)進(jìn)行了系統(tǒng)研究。他們發(fā)現(xiàn),，該基因中大部分的人類特異突變位點(diǎn)都會(huì)改變其對下游基因的調(diào)控效應(yīng),。這表明MCPH1基因在人類與非人靈長類之間已經(jīng)發(fā)生了明顯的功能分化,，并且這種功能分化可能是導(dǎo)致人類起源時(shí)大腦容量急劇擴(kuò)增的關(guān)鍵動(dòng)因之一。（生物谷Bioon.com）
生物谷推薦英文摘要：
BMC Biology DOI：10.1186/1741-7007-11-62
Functional divergence of the brain-size regulatinggene MCPH1 during primate evolution and theorigin of humans
Lei Shi, Ming Li, Qiang Lin, Xuebin Qi and Bing Su
Background One of the key genes that regulate human brain size, MCPH1 has evolved under strong Darwinian positive selection during the evolution of primates. During this evolution, the divergence of MCPH1 protein sequences among primates may have caused functional changes that contribute to brain enlargement. Results To test this hypothesis, we used co-immunoprecipitation and reporter gene assays to examine the activating and repressing effects of MCPH1 on a set of its down-stream genes and then compared the functional outcomes of a series of mutant MCPH1 proteins that carry mutations at the human- and great-ape-specific sites. The results demonstrate that the regulatory effects of human MCPH1 and rhesus macaque MCPH1 are different in 3 of 8 down-stream genes tested (p73, cyclinE1 and p14ARF), suggesting a functional divergence of MCPH1 between human and non-human primates. Further analyses of the mutant MCPH1 proteins indicated that most of the human-specific mutations could change the regulatory effects on the downstream genes. A similar result was also observed for one of the four great-ape-specific mutations. Conclusions Collectively, we propose that during primate evolution in general and human evolution in particular, the divergence of MCPH1 protein sequences under Darwinian positive selection led to functional modifications, providing a possible molecular mechanism of how MCPH1 contributed to brain enlargement during primate evolution and human origin.
