近日,，中國(guó)科學(xué)院昆明動(dòng)物研究所張亞平院士和云南大學(xué)研究員于黎,，碩士研究生王小燕等對(duì)疣猴亞科7個(gè)屬共10個(gè)代表物種的RNASE1基因進(jìn)行系統(tǒng)和深入的研究，與以往只基于少量疣猴亞科代表物種的研究對(duì)比,，該研究結(jié)果發(fā)現(xiàn)基于編碼區(qū),，非編碼區(qū)和基因全長(zhǎng)構(gòu)建的系統(tǒng)發(fā)育樹都支持RNASE1基因重復(fù)發(fā)生在亞洲葉猴和非洲葉猴物種形成之后，即獨(dú)立重復(fù)假說,。而且,，沒有發(fā)現(xiàn)明顯的基因轉(zhuǎn)換證據(jù)，并不支持一次重復(fù)假說中提出的基因轉(zhuǎn)換在疣猴亞科RNASE1進(jìn)化中起重要作用的觀點(diǎn),。此外,，選擇壓力分析也在重復(fù)基因拷貝的祖先枝上檢測(cè)到了正選擇作用。而且,，也檢測(cè)到了以前研究中沒有發(fā)現(xiàn)的正選擇位點(diǎn)和平行替換位點(diǎn),，這為后續(xù)的功能實(shí)驗(yàn)奠定了基礎(chǔ)。該研究結(jié)果不僅提供了更為清晰的疣猴亞科RNASE1基因進(jìn)化模式,，而且更全面了解了疣猴亞科物種獨(dú)特的以樹葉為食的適應(yīng)性進(jìn)化遺傳基礎(chǔ),。該研究工作得到了國(guó)際同行的高度評(píng)價(jià)，他們認(rèn)為“這項(xiàng)研究不只對(duì)疣猴亞科物種的研究非常重要,，而且對(duì)于其它靈長(zhǎng)類,，以及更廣的科學(xué)領(lǐng)域也尤為重要”。
胰核糖核酸酶（RNASE1）是非常重要的消化酶,，是研究基因進(jìn)化以及新功能產(chǎn)生的一個(gè)重要基因家族,。早期進(jìn)化分析表明RNASE1基因重復(fù)與靈長(zhǎng)目疣猴亞科物種適應(yīng)以樹葉為食的功能適應(yīng)緊密相關(guān)。然而,，關(guān)于RNASE1基因重復(fù)在疣猴亞科亞洲葉猴和非洲葉猴中的進(jìn)化模式目前存在著兩種截然不同的假說：一是Zhang等人在2006年基于基因全長(zhǎng)分析提出的獨(dú)立重復(fù)假說（independent duplication hypothesis）,，即RNASE1基因重復(fù)發(fā)生在亞洲葉猴和非洲葉猴分歧之后,，在亞洲葉猴和非洲葉猴中獨(dú)立產(chǎn)生；二是Schienman等（2006）和Xu 等(2009)基于編碼區(qū)分析提出的一次重復(fù)假說（one duplication event hypothesis）,，即基因重復(fù)發(fā)生在亞洲葉猴和非洲葉猴分歧之前,，并認(rèn)為基于非編碼區(qū)和基因全長(zhǎng)分析得到的獨(dú)立重復(fù)假說是由于基因間頻繁的基因轉(zhuǎn)換造成的。（生物谷Bioon.com）
生物谷推薦原始出處：
Molecular Biology and Evolution, doi:10.1093/molbev/msp216
Adaptive evolution of digestive RNASE1 genes in leaf-eating monkeys revisited: new insights from 10 additional Colobines
Li Yu*,$, Xiao-yan Wang*,$, Wei Jin*, Peng-tao Luan*, Nelson Ting and Ya-ping Zhang*,
* Laboratory for Conservation and Utilization of Bio-resource & Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, 650091, PR, China
State Key Laboratory of Genetic Resources and Evolution, and Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Kunming 650223, China
Anthropology Program, City University of New York Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA
Pancreatic RNase genes implicated in the adaptation of the colobine monkeys to leaf-eating have long intrigued evolutionary biologists since the identification of a duplicated RNASE1 gene with enhanced digestive efficiencies in Pygathrix nemaeus. The recent emergence of two contrasting hypotheses, i.e., independent duplication and one duplication event hypotheses, make it into focus again. Current understanding of Colobine RNASE1 gene evolution largely depends on the analyses of few colobine species. The present study with more intensive taxonomic and character sampling not only provides a clearer picture of Colobine RNASE1 gene evolution, but also allows to have a more thorough understanding about the molecular basis underlying the adaptation of Colobinae to the unique leaf-feeding lifestyle. The present broader and detailed phylogenetic analyses yielded two important findings: (1) All trees based on the analyses of coding, noncoding and both regions provided consistent evidence indicating RNASE1 duplication occurred after Asian and African colobines speciation, i.e., independent duplication hypothesis; (2) No obvious evidence of gene conversion in RNASE1 gene was found, favoring independent evolution of Colobine RNASE1 gene duplicates. The conclusion drawn from previous studies that gene conversion has played a significant role in the evolution of Colobine RNASE1 was not supported. Our selective constraint analyses also provided interesting insights, with significant evidence of positive selection detected on ancestor lineages leading to duplicated gene copies. The identification of a handful of new adaptive sites and amino acid changes that have not been characterized previously also provide a necessary foundation for further experimental investigations of RNASE1 functional evolution in Colobinae.
