选择性剪切（alternative splicing）是一个基因编码出不同转录本和蛋白质的重要途径，对满足生物体所需蛋白多样性具有重要意义。此前的研究显示，新基因通常在序列、基因结构和表达模式上与其祖先基因发生快速的分化。基因结构的改变可能伴随着选择性剪切的改变，但关于新基因选择性剪切的进化还未被研究过。
昆明动物研究所中德马普进化基因组学青年科学家小组的博士生占祖兵等在导师王文研究员的指导下，对之前该研究组从黑腹果蝇内鉴定出的新基因做了基因内选择性剪切的改变以及其改变的序列基础与功能后果的分析。结果显示，选择性剪切的新基因比祖先基因所占的比例要少，提示新基因起源后倾向于丢失选择性剪切。逆转座、部分基因复制和完整的基因复制，都能导致选择性剪切的丢失，这说明选择性剪切的丢失是新基因起源和进化的机制之一。通过EST分析，进一步发现选择性剪切改变的新基因表达水平比祖先基因更低，表达组织更少，而且更倾向于在精巢内表达。这些发现提示，选择性剪切改变后获得了与其祖先基因在结构、表达与功能上的分化。题为“Evolution of alternative splicing in newly evolved genes of Drosophila”的该论文已发表于《Gene》杂志上。（生物谷Bioon.com）
生物谷推荐原文出处：
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.
