摘要：

Knowledge on ancient life and their interaction with the early planet relies largely on fossil records. Unlike animals and plants, heterotrophic bacteria were rarely preserved as fossils, and thus their evolutionary history remains poorly understood. Here, we developed a fossil-independent approach to understand the evolutionary timescale of marine Roseobacters, an alphaproteobacterial lineage dominantly associated with eukaryotic phytoplankton groups and playing a prominent role in global carbon and sulfur cycles. This approach is based on the spontaneous mutation rate (1.39×10-10 per nucleotide per cell division) determined for a model Roseobacter strain using a mutation accumulation experiment and growth rates typical for the taxon in the ocean. It first gives estimates of evolutionary time for closely related taxa, and subsequently extrapolates the timing estimates for more divergent lineages by leveraging the molecular clock approach. Working on ~200 gene families showing evidence of molecular clocks over the Roseobacter evolutionary history, this approach gives an estimated date of Roseobacter genome expansion in good agreement with an earlier fossil-based estimate of approximately 250 million years ago and is consistent with a hypothesis of a correlated evolutionary history between roseobacters and marine eukaryotic phytoplankton groups.

個人簡歷：

羅海偉博士2004年獲廈門大學環境科學學士學位；2008年獲美國南卡羅萊娜大學海洋微型生物學碩士學位；2010年獲該校分子進化生物學和生物信息學博士學位，師從國際知名群體遺傳學家Austin Hughes；2010-2014年在美國喬治亞大學海洋學系從事博士后研究，師從國際知名海洋微生物生態學家Mary Ann Moran；2015年起開始擔任香港中文大學生命科學學院助理教授、博士生導師。近5年來，已發表了三十多篇SCI論文，均刊登在PNAS, ISME Journal等主流學術雜志上，其中影響因子超過9.0的以第一作者或者通訊作者發表的文章有10篇，他引800余次。曾多次被包括香港大學、韓國仁荷大學、沙特阿拉伯阿卜杜拉國王科技大學、臺灣中央研究院生物多樣性研究所、中科院土壤所和南海所、國家海洋局二所、同濟大學等國內外知名高校和研究所邀請做學術訪問。兩次擔任美國國家自然科學基金項目的特邀評審員和包括PNAS、ISME Journal在內的20多本國際主流雜志的特約審稿人。自2015年起，作為課題負責人獲得了香港研資局（RGC）和香港環境與自然保育基金（ECF）等多項資助。目前羅海偉博士領導的香港中文大學海洋微生物學研究團隊由6名博士生、4名博士后和多名客座研究人員組成。