Appalachian Laboratory, University of Maryland Center for Environmental Science, Frostburg, Maryland, USA.
PLoS One. 2010 May 24;5(5):e10785. doi: 10.1371/journal.pone.0010785.
Lateral gene transfer (LGT) appears to promote genotypic and phenotypic variation in microbial communities in a range of environments, including the mammalian intestine. However, the extent and mechanisms of LGT in intestinal microbial communities of non-mammalian hosts remains poorly understood.
METHODOLOGY/PRINCIPAL FINDINGS: We sequenced two fosmid inserts obtained from a genomic DNA library derived from an agar-degrading enrichment culture of marine iguana fecal material. The inserts harbored 16S rRNA genes that place the organism from which they originated within Clostridium cluster IV, a well documented group that habitats the mammalian intestinal tract. However, sequence analysis indicates that 52% of the protein-coding genes on the fosmids have top BLASTX hits to bacterial species that are not members of Clostridium cluster IV, and phylogenetic analysis suggests that at least 10 of 44 coding genes on the fosmids may have been transferred from Clostridium cluster XIVa to cluster IV. The fosmids encoded four transposase-encoding genes and an integrase-encoding gene, suggesting their involvement in LGT. In addition, several coding genes likely involved in sugar transport were probably acquired through LGT.
Our phylogenetic evidence suggests that LGT may be common among phylogenetically distinct members of the phylum Firmicutes inhabiting the intestinal tract of marine iguanas.
水平基因转移（LGT）似乎在多种环境中促进微生物群落的基因型和表型变异，包括哺乳动物肠道。然而，非哺乳动物宿主肠道微生物群落中 LGT 的程度和机制仍知之甚少。
方法/主要发现：我们对从海洋鬣蜥粪便物质琼脂降解富集培养物中获得的两个 fosmid 插入片段进行了测序。插入片段包含 16S rRNA 基因，它们所源自的生物体属于梭菌簇 IV，这是一个记录良好的栖息在哺乳动物肠道中的群体。然而，序列分析表明，fosmid 上 52%的编码蛋白基因与不属于梭菌簇 IV 的细菌物种的 BLASTX 命中最高，系统发育分析表明，fosmid 上至少有 10 个编码基因可能是从梭菌簇 XIVa 转移到簇 IV 的。fosmid 编码了四个转座酶编码基因和一个整合酶编码基因，表明它们参与了 LGT。此外，几个可能参与糖转运的编码基因可能是通过 LGT 获得的。
我们的系统发育证据表明，LGT 可能在栖息在海洋鬣蜥肠道中的厚壁菌门中不同的分类群成员中很常见。
