Kuramae Eiko E, Robert Vincent, Snel Berend, Boekhout Teun
Centraalbureau voor Schimmelcultures, Comparative Genomics and Bioinformatics, Uppsalalaan 8, 3584 Utrecht, The Netherlands.
Genomics. 2006 Oct;88(4):387-93. doi: 10.1016/j.ygeno.2006.07.001. Epub 2006 Aug 9.
The phylogenetic position of the fission yeast Schizosaccharomyces pombe in the fungal Tree of Life is still controversial. Three alternative phylogenetic positions have been proposed in the literature, namely (1) a position basal to the Hemiascomycetes and Euascomycetes, (2) a position as a sister group to the Euascomycetes with the Hemiascomycetes as a basal branch, or (3) a sister group to the Hemiascomycetes with Euascomycetes as a basal branch. Here we compared 91 clusters of orthologous proteins containing a single orthologue that are shared by 19 eukaryote genomes. The major part of these 91 orthologues supports a phylogenetic position of S. pombe as a basal lineage among the Ascomycota, thus supporting the second proposition. Interestingly, part of the orthologous proteins supported a fourth, not yet described alternative, in which S. pombe is basal to both Basidiomycota and Ascomycota. Both topologies of phylogenetic trees are well supported. We believe that both reflect correctly the phylogenetic history of the species concerned. This apparent paradox may point to a heterogeneous nuclear genome of the fungi. Importantly, this needs to be taken in consideration for a correct understanding of the fungal Tree of Life.
裂殖酵母粟酒裂殖酵母在真菌生命之树中的系统发育位置仍存在争议。文献中提出了三种不同的系统发育位置，即：(1) 位于半子囊菌和真子囊菌基部的位置；(2) 作为真子囊菌的姐妹群，半子囊菌为基部支系的位置；或 (3) 作为半子囊菌的姐妹群，真子囊菌为基部支系的位置。在此，我们比较了由19个真核生物基因组共享的、包含单个直系同源物的91个直系同源蛋白簇。这91个直系同源物中的大部分支持粟酒裂殖酵母在子囊菌门中作为基部谱系的系统发育位置，从而支持了第二种观点。有趣的是，部分直系同源蛋白支持了第四种尚未描述的观点，即粟酒裂殖酵母位于担子菌门和子囊菌门两者的基部。系统发育树的这两种拓扑结构都得到了有力支持。我们认为两者都正确反映了相关物种的系统发育历史。这种明显的矛盾可能表明真菌的核基因组是异质的。重要的是，为了正确理解真菌生命之树，需要考虑到这一点。
