Computational & Systems Biology Initiative, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Nature. 2011 Jan 6;469(7328):93-6. doi: 10.1038/nature09649. Epub 2010 Dec 19.
The natural history of Precambrian life is still unknown because of the rarity of microbial fossils and biomarkers. However, the composition of modern-day genomes may bear imprints of ancient biogeochemical events. Here we use an explicit model of macroevolution including gene birth, transfer, duplication and loss events to map the evolutionary history of 3,983 gene families across the three domains of life onto a geological timeline. Surprisingly, we find that a brief period of genetic innovation during the Archaean eon, which coincides with a rapid diversification of bacterial lineages, gave rise to 27% of major modern gene families. A functional analysis of genes born during this Archaean expansion reveals that they are likely to be involved in electron-transport and respiratory pathways. Genes arising after this expansion show increasing use of molecular oxygen (P = 3.4 × 10(-8)) and redox-sensitive transition metals and compounds, which is consistent with an increasingly oxygenating biosphere.
由于微生物化石和生物标志物的稀有性，前寒武纪生命的自然历史仍然未知。然而，现代基因组的组成可能带有古代生物地球化学事件的印记。在这里，我们使用一个包含基因诞生、转移、复制和丢失事件的明确的宏观进化模型，将 3983 个基因家族的进化史映射到地质时间线上，跨越生命的三个领域。令人惊讶的是，我们发现，太古宙时期的一段短暂的遗传创新时期，与细菌谱系的快速多样化相吻合，产生了 27%的主要现代基因家族。对这个太古宙扩张期间产生的基因的功能分析表明，它们可能参与电子传递和呼吸途径。在这个扩张之后出现的基因显示出对分子氧（P = 3.4×10(-8))和氧化还原敏感的过渡金属和化合物的使用增加，这与一个越来越富氧的生物圈是一致的。
