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← Rare Protozoan from Sludge in Norwegian Lake Does Not Fit On Main Branches of Tree of Life

Opisthokont's Avatar Jump to comment 4 by Opisthokont

Neodarwinian -- actually 'protozoan' is used in the protistological community, as it unambiguously denotes heterotrophic single-celled eukaryotes. And 'eucaryotic' is an accepted alternative spelling; in fact, the name for our domain is 'Eucarya', with a 'c'. The term comes from Greek roots, though, so it is more proper to spell it with a 'k', which most of us do.

As for 'unknown': the paper itself shows that it fits onto a known but understudied branch of eukaryote diversity. I think all of us in the community (including Shalchian-Tabrizi) are extremely sceptical of that, but the data so far seem consistent. Specifically, the organism with which it groups (called Malawimonas, since the first members of the genus were sampled from Lake Malawi) is itself an unplaced branch of eukaryote diversity. Malawimonas very closely resembles other organisms with which it doesn't show much genetic affinity, and it doesn't resemble Collodictyon particularly closely (well, aside from their both being 'protozoans' -- see, the word is useful!). Other analyses have placed Collodictyon as belonging to a number of other groups: its position in the Tree of Life has been unstable. The main difference with the current paper is that they obtained a lot more data from Collodictyon -- previous analyses were done with only one gene, while this one used many more -- and got a fair amount of support for one particular placement in the Tree. At the same time, the amount of data for Collodictyon is still much smaller than that for many other organisms included in the analysis, and it is quite possible that more protist data (both from Collodictyon and from other organisms) will change its position in future phylogenetic analyses.

Fri, 27 Apr 2012 14:36:09 UTC | #937739