Lücking Robert, Huhndorf Sabine, Pfister Donald H, Plata Eimy Rivas, Lumbsch H Thorsten
Department of Botany, The Field Museum, 1400 South Lake Shore Drive, Chicago, Illinois 60605-2496, USA.
Mycologia. 2009 Nov-Dec;101(6):810-22. doi: 10.3852/09-016.
Dating of fungal divergences with molecular clocks thus far has yielded highly inconsistent results. The origin of fungi was estimated at between 660 million and up to 2.15 billion y ago, and the divergence of the two major lineages of higher fungi, Ascomycota and Basidiomycota, at between 390 million y and up to 1.5 billion y ago. Assuming that these inconsistencies stem from various causes, we reassessed the systematic placement of the most important fungal fossil, Paleopyrenomycites, and recalibrated internally unconstrained, published molecular clock trees by applying uniform calibration points. As a result the origin of fungi was re-estimated at between 760 million and 1.06 billion y ago and the origin of the Ascomycota at 500-650 million y ago. These dates are much more consistent than previous estimates, even if based on the same phylogenies and molecular clock trees, and they are also much better in line with the fossil record of fungi and plants and the ecological interdependence between filamentous fungi and land plants. Our results do not provide evidence to suggest the existence of ancient protolichens as an alternative to explain the ecology of early terrestrial fungi in the absence of land plants.
迄今为止,利用分子钟确定真菌分化时间得到的结果高度不一致。真菌起源时间估计在6.6亿至21.5亿年前,而高等真菌的两个主要谱系——子囊菌门和担子菌门的分化时间在3.9亿至15亿年前。假设这些不一致源于多种原因,我们重新评估了最重要的真菌化石——古双盘菌属的系统位置,并通过应用统一的校准点,对已发表的内部无约束分子钟树进行重新校准。结果,真菌起源时间重新估计在7.6亿至10.6亿年前,子囊菌门的起源时间在5亿至6.5亿年前。即使基于相同的系统发育和分子钟树,这些日期也比之前的估计更加一致,而且它们也更符合真菌和植物的化石记录以及丝状真菌与陆地植物之间的生态相互依存关系。我们的结果没有提供证据表明存在古代原始地衣,以作为在没有陆地植物的情况下解释早期陆地真菌生态的另一种方式。