Functional and Comparative Genomics, School of Biological Sciences, University of Liverpool, Crown St., Liverpool L69 7ZB, UK.
Curr Opin Microbiol. 2015 Feb;23:102-9. doi: 10.1016/j.mib.2014.11.012. Epub 2014 Dec 1.
Pseudogenes are defined as fragments of once-functional genes that have been silenced by one or more nonsense, frameshift or missense mutations. Despite continuing increases in the speed of sequencing and annotating bacterial genomes, the identification and categorisation of pseudogenes remains problematic. Even when identified, pseudogenes are considered to be rare and tend to be ignored. On the contrary, pseudogenes are surprisingly prevalent and can persist for long evolutionary time periods, representing a record of once-functional genetic characteristics. Most importantly, pseudogenes provide an insight into prokaryotic evolutionary history as a record of phenotypic traits that have been lost. Focusing on the intracellular and symbiotic bacteria in which pseudogenes predominate, this review discusses the importance of identifying pseudogenes to fully understand the abilities of bacteria, and to understand prokaryotes within their evolutionary context.
假基因被定义为曾经具有功能的基因的片段，这些基因已经通过一个或多个无意义、移码或错义突变而沉默。尽管细菌基因组测序和注释的速度不断提高，但假基因的识别和分类仍然存在问题。即使被识别出来，假基因也被认为是罕见的，往往被忽视。相反，假基因却出人意料地普遍存在，可以在很长的进化时期内持续存在，代表了曾经具有功能的遗传特征的记录。最重要的是，假基因提供了对原核生物进化历史的深入了解，是已经失去的表型特征的记录。本文聚焦于假基因占主导地位的细胞内共生细菌，讨论了识别假基因的重要性，以充分了解细菌的能力，并在进化背景下理解原核生物。
