Juergen Brosius, Ph.D.

Professor & Director, University of Munster, Germany

教授，德国明斯特大学实验病理学研究所主任，四川大学华西医院系统遗传研究院特聘教授、非全职专家，国际著名分子遗传和演化生物学家。其在以下科学领域有突出的贡献：首个核糖体RNA操作子的遗传测序、基因表达的质粒设计、重组蛋白和RNA的高表达、RNA生物学、RNA组学、转座子元件、生命的起源和演化等。目前，其在相关领域发表文章逾300篇，引用近2万次，h指数高达73。

The evolution of genes and genomes

For many decades it had been known that novel genes arise by duplication of existing genes whereby one copy usually remains under negative selection and the other one is free to change. De novo origination of genes was thought to be rare. However, genomes of multicellular organism usually harbor a large proportion of unused space. Background transcription (transcriptional noise) provides a large reservoir of transcripts upon which natural selection could act. Should such a transcript turn out to be beneficial to the cell and persist over evolutionary time, such events underlie the birth of a novel RNA gene. At a later point, fortuitous changes that lead to acquisition of an open reading frame and translational regulatory elements (e.g., ribosome binding site, Kozak sequence, poly(A) addition signal) as well as changes that lead to an open reading frame (ORF) might convert such an RNA to a messenger RNA. Once more, if the resulting polypeptide should be beneficial for the cell and persist over evolutionary time, such a sequence of events would mark the birth of a novel protein coding gene.
A much more frequent event is the recruitment (exaptation) of novel gene parts (modules) to existing genes out of hitherto neutrally evolving genomic regions (gene flanking or intronic). Examples for RNA genes and protein coding genes will be presented.

参考译文

基因和基因组演化

多年来人们就已经知道新基因是通过已有基因的复制产生的，一个拷贝一直处于负选择下，而另一个可自由变化。从头产生的基因一直认为很稀有。然而，多细胞物种的基因组存在大量的未使用空间。转录背景或者转录噪音蓄有大量能受到自然选择的转录本。这样的转录本是应该有益于细胞从而随着进化时间而得以保留，那么这样的事件成为了新RNA基因产生的基础。随后，能导致获取开放式阅读框和转录调控元件（如核糖体结合位点，Kozak序列，polyA附加信号）的偶然事件和产生开放式阅读款的改变可能将该RNA转程了信使RNA。接着，如果产生的多肽有益于细胞且随着进化过程得以保留，这样的一系列事件将标志着一个新的蛋白编码基因的诞生。
更常见的是已有基因源于迄今为止中性进化的基因区间（如基因侧翼或内部的）产生的功能变异。报告将展示RNA基因和蛋白质编码基因的例子。