Category Archives: genome reduction

Multiple Losses of sex within Microsporidia

Blogging about Peer-Reviewed ResearchA recent paper I found interesting (and I am sure was interesting to Dr Logsdon) about Multiple losses of sex within a single genus of Microsporidia. In the paper Joseph Ironside describes multiple instances of loss of sex within the Nosema/Vairimorpha group testing the hypothesis that the ancestral lineage was asexual. The group of species are undergoing rapid evolution where changes in lifestyle/lifecycle can occur even among very closely related lineages. In order to do test a formal hypothesis about whether the ancestor was asexual or sexual this the author had to improve the resolution of the phylogenetic relationships of these species and deal with some technical problems due to mutational biases in the rDNA sequences. The result he found was that the ancestral lineage was sexual and that asexuality arose multiple times among these species. He also provides a caution:

“The rapid evolution of microsporidian life cycles indicated by this study also suggests that even closely related microsporidia cannot be assumed to have similar life cycles and the life cycle of each newly discovered species must therefore be completely described.”

Something one has to be careful about in comparative studies of these species.

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