隱藏在當今活生物的現(xiàn)代基因組中的,，是古代生物地化事件留下的印記。Lawrence David 和 Eric Alm建立了用來重構(gòu)古基因組的一個新算法,，該算法將橫向基因轉(zhuǎn)移的混淆效應(yīng)及系統(tǒng)發(fā)生上的不確定性考慮了進去,。將這個算法應(yīng)用于來自當今生物的約10萬個基因序列,，他們發(fā)現(xiàn)了地球歷史上重大事件的遺傳印記,，包括開始于距今25億多年前的氧含量的逐漸升高，以及以前沒有報道過的,、發(fā)生在太古代（在距今超過20億年前的“寒武紀大爆發(fā)”之前）的雖然短暫但卻巨大的遺傳多樣性增加。（生物谷Bioon.com）
生物谷推薦原文出處：
Nature doi:10.1038/nature09649
Rapid evolutionary innovation during an Archaean genetic expansion
Lawrence A. David& Eric J. Alm
The natural history of Precambrian life is still unknown because of the rarity of microbial fossils and biomarkers1, 2. However, the composition of modern-day genomes may bear imprints of ancient biogeochemical events3, 4, 5, 6. 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.
