Azarian Taj, Huang I-Ting, Hanage William P.
College of Medicine, University of Central Florida, Orlando, FL, USA
Center for Communicable Disease Dynamics, Department of Epidemiology, T.H. Chan School of Public Health, Harvard University, Boston, MA, USA
Prokaryotes demonstrate tremendous variation in gene content, even within individual bacterial clones or lineages. This diversity is made possible by the ability of bacteria to horizontally transfer DNA through a variety of mechanisms, and the extent of such transfer sets them apart from eukaryotes. What has become evident through interrogation of thousands of bacterial genomes is that gene variation is directly related to the ecology of the organism and is driven by continual processes of niche exploration, diversification, and adaptation. Of course, the acquisition of new genes is not necessarily beneficial, resulting in either the removal of that individual through purifying selection or the occurrence of compensatory mutations in the genomic “backbone” (i.e., core genes) that become epistatically linked to the presence accessory genes. There are now numerous examples of relationship between gene variation and niche adaptation. We explore some of those examples here as well as the population genomic footprint left by the dynamics of gene flow, diversification, and adaptation.
原核生物在基因内容上表现出巨大的差异，即使在单个细菌克隆或谱系中也是如此。细菌通过多种机制水平转移DNA的能力使得这种多样性成为可能，而这种转移的程度将它们与真核生物区分开来。通过对数千个细菌基因组的研究，已经很明显的是，基因变异与生物体的生态直接相关，并由生态位探索、多样化和适应的持续过程驱动。当然，获得新基因不一定是有益的，这会导致通过纯化选择去除该个体，或者在基因组“主干”（即核心基因）中发生补偿性突变，这些突变与存在的辅助基因发生上位性连锁。现在有许多基因变异与生态位适应之间关系的例子。我们在这里探讨其中一些例子，以及基因流动、多样化和适应动态留下的群体基因组足迹。
