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Gene：選擇性剪切在果蠅新基因中的進化
閱讀：759 發布時間：2010-12-9| 選擇性剪切（alternative splicing）是一個基因編碼出不同轉錄本和蛋白質的重要途徑，對滿足生物體所需蛋白多樣性具有重要意義。此前的研究顯示，新基因通常在序列、基因結構和表達模式上與其祖先基因發生快速的分化。基因結構的改變可能伴隨著選擇性剪切的改變，但關于新基因選擇性剪切的進化還未被研究過。 昆明動物研究所中德馬普進化基因組學青年科學家小組的博士生占祖兵等在導師王文研究員的指導下，對之前該研究組從黑腹果蠅內鑒定出的新基因做了基因內選擇性剪切的改變以及其改變的序列基礎與功能后果的分析。結果顯示，選擇性剪切的新基因比祖先基因所占的比例要少，提示新基因起源后傾向于丟失選擇性剪切。逆轉座、部分基因復制和完整的基因復制，都能導致選擇性剪切的丟失，這說明選擇性剪切的丟失是新基因起源和進化的機制之一。通過EST分析，進一步發現選擇性剪切改變的新基因表達水平比祖先基因更低，表達組織更少，而且更傾向于在精巢內表達。這些發現提示，選擇性剪切改變后獲得了與其祖先基因在結構、表達與功能上的分化。題為“Evolution of alternative splicing in newly evolved genes of Drosophila”的該論文已發表于《Gene》雜志上。（生物谷Bioon.com） 原文出處： Gene. 2011 Jan 1;470（1-2）:1-6. Epub 2010 Sep 16. Evolution of alternative splicing in newly evolved genes of Drosophila. Zhan Z, Ren J, Zhang Y, Zhao R, Yang S, Wang W. CAS-Max Planck Junior Research Group, State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China. Abstract New gene origination is a fundamental process underlying evolution of biological diversity. Although new genes usually evolve rapidly in sequences, structure and expression, the evolutionary pattern of alternative splicing （AS） in new genes and the molecular mechanisms involved in this alternation remain to be explored. Here, we used the new genes identified in the Drosophila melanogaster lineage to study alternation of AS and the possible functional consequences of these genes. We found that new genes tended to exhibit low degree of AS, though a few new genes were alternatively spliced. Interestingly loss of introns in retroposed new genes can only account for one third of the low-level AS in new genes, while partial gene duplication without AS exons and mutations in the duplicated AS exons/introns together have resulted in two-third AS losses in new genes, indicating that reducing the degree of AS is a general trend in all categories of new genes. Further investigations on tissue expression patterns of these new genes showed that those with AS alternation had a relatively lower expression level, were expressed in fewer tissues and tended to be more likely expressed in testis than their parental genes. All these observations imply that these new genes may have gained diverged structures and expression patterns from their parental genes after AS alternation. | ||