A data mining approach to dinoflagellate clustering according to sterol composition: correlations with evolutionary history

Abstract

This study examined the sterol compositions of 102 dinoflagellates using clustering and cluster validation techniques, as a means of determining the relatedness of the organisms. In addition, dinoflagellate sterol-based relationships were compared statistically to 18S rDNA-based phylogenetic relationships using the Mantel test. Our results indicated that the examined dinoflagellates formed six clusters based on sterol composition and that several, but not all, dinoflagellate genera, which formed discrete clusters in the 18S rDNA-based phylogeny, shared similar sterol compositions. This and other correspondences suggest that the sterol compositions of dinoflagellates are explained, to a certain extent, by the evolutionary history of this lineage.

Free Sterol Composition of Species in the Dinoflagellate GenusPyrocystis: A Spectrum of Sterol Diversity

“…The tighter sterol composition relationship of P. fusiformis to P. noctiluca than to P. lunula reinforces the earlier conclusions of Leblond et al (2010), who found P. fusiformis and P. noctiluca to be members of a cluster of dinoflagellates that produce dinosterol as their primary sterol. The spectrum of sterol composition diversity amongst cholesterol and dinosterol exhibited here by the genus Pyrocystis is also seen in a similar fashion in the genus, Alexandrium .…”

“…However, Alexandrium andersoni produces cholesterol as its primary sterol, but is unable to produce dinosterol. It is interesting to note that the genus Alexandrium is closely related to the genus Pyrocystis as based on an 18S rDNA phylogeny (Leblond et al 2010). Indeed, it has been observed by Leblond et al (2010) that dinoflagellates with similar 18S rRNA gene sequences produce similar sets of sterols, thus implying that these two unrelated traits have evolved in parallel.…”

“…Leblond et al (2010) have briefly mentioned the sterol composition of two other species, Pyrocystis fusiformis and Pyrocystis noctiluca , in a data‐mining study, which found dinoflagellates to organize into clusters according to sterol composition. However, we feel that the sterol composition of this particular genus deserves a more in‐depth examination than what was presented in Leblond et al (2010) because that study left most of the sterols undescribed. By presenting a more detailed account of the sterols of P. fusiformis and P. noctiluca , this study enhances our knowledge of dinoflagellate lipid biochemistry, with an emphasis on the comparative sterol diversity in the genus Pyrocystis .…”

Sterol Composition and Biosynthetic Genes of the Recently Discovered Photosynthetic Alveolate, Chromera velia (Chromerida), a Close Relative of Apicomplexans

“…A comparison to the sterols produced by dinoflagellates as the next closest group with the ability to produce sterols related to C. velia reveals that they do not possess the sterols observed in C. velia [see summary presented by Leblond et al. ()]. Rather, the identified sterols of C. velia have been observed in other, seemingly unrelated classes of photoautotrophic microalgae, such as chlorarachniophytes (Leblond et al.…”

“…For example, clustering dinoflagellates based on their sterol composition forms groups that generally support their phylogenetic organization as based on SSU rRNA gene sequences (Leblond et al. ). Sterols also have the potential to serve as biomarkers for particular algae, and this is particularly true for dinoflagellates.…”