Max-Planck Institute for Evolutionary Biology, August-Thienemannstrasse 2, 24306 Ploen, Germany.
Curr Biol. 2009 Sep 29;19(18):1527-31. doi: 10.1016/j.cub.2009.07.049. Epub 2009 Sep 3.
It is generally assumed that new genes would arise by gene duplication mechanisms, because the signals for regulation and transcript processing would be unlikely to evolve in parallel with a new gene function. We have identified here a transcript in the house mouse (Mus musculus) that has arisen within the past 2.5-3.5 million years in a large intergenic region. The region is present in many mammals, including humans, allowing us to exclude the involvement of gene duplication, transposable elements, or other genome rearrangements, which are typically found for other cases of newly evolved genes. The gene has three exons, shows alternative splicing, and is specifically expressed in postmeiotic cells of the testis. The transcript is restricted to species within the genus Mus and its emergence correlates with indel mutations in the 5' regulatory region of the transcript. A recent selective sweep is associated with the transcript region in M. m. musculus populations. A knockout in the laboratory strain BL6 results in reduced sperm motility and reduced testis weight. Our results show that cryptic signals for transcript regulation and processing exist in intergenic regions and can become the basis for the evolution of a new functional gene.
人们普遍认为新基因是通过基因复制机制产生的，因为调节和转录加工的信号不太可能与新基因功能平行进化。我们在这里鉴定出了小家鼠（Mus musculus）中的一种转录本，它是在过去 250 万至 350 万年前在一个大型基因间区产生的。该区域存在于许多哺乳动物中，包括人类，这使我们能够排除基因复制、转座元件或其他基因组重排的参与，这些通常是其他新进化基因的情况。该基因有三个外显子，表现出选择性剪接，并且特异性表达在睾丸的减数分裂后细胞中。该转录本仅限于 Mus 属内的物种，其出现与转录本 5'调控区的插入缺失突变相关。最近的选择性清除与 M. m. musculus 群体中的转录本区域相关。实验室品系 BL6 中的敲除导致精子运动能力降低和睾丸重量减轻。我们的结果表明，基因间区存在隐藏的转录调控和加工信号，可成为新功能基因进化的基础。
