Genomic diversity and population dynamics in natural microbial communities

点击翻译按钮获取中文摘要

Bacteria in nature rarely live in pure culture; rather, they form complex communities that have profound effects on our world. For example, the numbers and types of nitrogen-fixing bacteria in soil can affect the quality of a crop, and the disruption of bacterial populations in the human intestine with antibiotics can lead to life-threatening infections. Since most bacteria cannot be cultivated in the lab, our knowledge of natural microbial communities is largely based on analysis of sequences of universally conserved genes found in all bacteria. At the same time, studies of culturable bacteria have revealed significant gene content differences between strains of bacteria that would be considered members of the same species if only universal gene sequence data were considered. There are clues in the results of sequence-based studies of microbial communities that the significance of genomic diversity in natural communities has been underestimated. Perturbation of microbial communities may select for strain-specific genes and result in biologically significant population shifts at the "sub-species" level that would be undetected by universal gene sequence-based approaches. An inventory of genomic diversity in a microbial community is an essential first step to understanding population dynamics at the strain level.