家蚕微孢子虫全基因组分析支持微孢子虫与真菌的亲缘关系

Genetic Relationship Between Microsporidia and Fungi is Supported by the Whole Genomic Analysis of Nosema bombycis

微孢子虫(microsporidia)是一类细胞内专性寄生的单细胞真核生物,虽然分子生物学的研究证据表明其与真菌(fun-gi)存在亲缘关系,但这些证据均是基于单个或少数几个基因构建系统进化树而得出的。利用家蚕微孢子虫全基因组数据,采用基于基因同源性的Darkhorse基因组统计方法,鉴定家蚕微孢子虫基因组中每个基因的来源谱系,并通过全基因组谱系可能性指数(lineage probability index,LPI)分析微孢子虫与其他物种的亲缘关系。结果表明家蚕微孢子虫与其他微孢子虫的LPI加权平均值为0.93,具有最近的亲缘关系,与真菌界的LPI加权平均值为0.65,与原生生物界的LPI加权平均值为0.38。由此证明微孢子虫与真菌存在着更近的亲缘关系,微孢子虫门属于真菌界而非原生生物界。

Microsporidia are a group of obligate intracellular eukaryotic parasites. Although more and more evidences have indicated the relationship between microsporidia and fungi, most of them are just based on the phylogenetic tree of single or few genes. Thus, by means of Darkhorse whole genomic statistics based on gene identities, we identified the lineage of each gene and calculated the lineage probability index （LPI） of the Nosema bombycis genome to analyze the genetic relationships between N. bombycis and other species. It was found that the weighted mean value of LPI between N. bombycis and other microsporidia is 0.93, that between N. bombycis and Fungi is 0.65, and that between N. bombycis and protista is 0.38. These results strongly suggest that microsporidia belongs to Fungi rather than Protista.