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Molecules illuminate morphology: Phylogenomics confirms convergent evolution among ‘oligotrichous’ ciliates
- 1.0479559 - BC 2018 RIV GB eng J - Journal Article
Lynn, D. H. - Kolísko, Martin
Molecules illuminate morphology: Phylogenomics confirms convergent evolution among ‘oligotrichous’ ciliates.
International Journal of Systematic and Evolutionary Microbiology. Roč. 67, č. 9 (2017), s. 3676-3682, č. článku 002060. ISSN 1466-5026. E-ISSN 1466-5034
Institutional support: RVO:60077344
Keywords : Oligotrichs * Oxytricha * Phylogeny * Strombidinopsis * Strombidium * Stylonychia
OECD category: Biochemistry and molecular biology
Impact factor: 1.932, year: 2017
Oligotrichous ciliates have been traditionally placed in a presumed monophyletic taxon called the Oligotrichia. However, gene sequences of the small subunit rRNA gene, and several other genes, suggest that the taxon is not monophyletic: although statistical support for this is not strong, the oligotrich Halteria grandinella is associated with the hypotrich ciliates and not with other oligotrich genera, such as Strombidium and Strombidinopsis. This has convinced some taxonomists to emphasize that morphological features strongly support the monophyly of the oligotrichs. To further test this hypothesis of monophyly, we have undertaken a phylogenomic analysis using the transcriptome of H. grandinella cells amplified by a single-cell technique. One hundred and twenty-six of 159 single-gene trees placed H. grandinella as sister to hypotrich species, and phylogenomic analyses based on a subset of 124 genes robustly rejected the monophyly of the Oligotrichia and placed the genus Halteria as sister to the hypotrich genera Stylonychia and Oxytricha. We use these phylogenomic analyses to assess the convergent nature of morphological features of oligotrichous ciliates. A particularly ‘strong’ morphological feature supporting monophyly of the oligotrichs is enantiotropic cell division, which our results suggest is nevertheless a convergent feature, arising through the need for dividing ciliates to undertake rotokinesis to complete cell division.
Permanent Link: http://hdl.handle.net/11104/0275540
Number of the records: 1