Pritham Ellen J
Department of Biology, University of Texas, Arlington, Arlington, TX 76019, USA.
J Hered. 2009 Sep-Oct;100(5):648-55. doi: 10.1093/jhered/esp065. Epub 2009 Aug 7.
Recent advances in genome sequencing have led to a vast accumulation of transposable element data. Consideration of the genome sequencing projects in a phylogenetic context reveals that despite the hundreds of eukaryotic genomes that have been sequenced, a strong bias in sampling exists. There is a general under-representation of unicellular eukaryotes and a dearth of genome projects in many branches of the eukaryotic phylogeny. Among sequenced genomes, great variation in genome size exists, however, little difference in the total number of cellular genes is observed. For many eukaryotes, the remaining genomic space is extremely dynamic and predominantly composed of a menagerie of populations of transposable elements. Given the dynamic nature of the genomic niche filled by transposable elements, it is evident that these elements have played an important role in genome evolution. The contribution of transposable elements to genome architecture and to the advent of genetic novelty is likely to be dependent, at least in part, on the transposition mechanism, diversity, number, and rate of turnover of transposable elements in the genome at any given time. The focus of this review is the discussion of some of the forces that act to shape transposable element diversity within and between genomes.
基因组测序的最新进展导致了转座元件数据的大量积累。在系统发育背景下对基因组测序项目进行考量后发现，尽管已经对数百个真核生物基因组进行了测序，但在样本选取上存在强烈的偏向性。单细胞真核生物普遍代表性不足，并且在真核生物系统发育的许多分支中缺乏基因组项目。在已测序的基因组中，基因组大小存在很大差异，然而，细胞基因的总数差异不大。对于许多真核生物来说，剩余的基因组空间极其动态，并且主要由大量的转座元件群体组成。鉴于转座元件所占据的基因组生态位的动态性质，很明显这些元件在基因组进化中发挥了重要作用。转座元件对基因组结构和遗传新奇性出现的贡献可能至少部分取决于转座机制、多样性、数量以及在任何给定时间基因组中转座元件的周转速率。本综述的重点是讨论一些影响基因组内部和基因组之间转座元件多样性形成的力量。
