Format

Send to

Choose Destination
Int J Syst Evol Microbiol. 2001 Nov;51(Pt 6):2211-9.

New insights into the phylogenetic position of diplonemids: G+C content bias, differences of evolutionary rate and a new environmental sequence.

Author information

1
División de Microbiología, Universidad Miguel Hernández, San Juan de Alicante, Spain. david.moreira@snv.jussieu.fr

Abstract

The phylum Euglenozoa consists of three distinct groups: the euglenoids, diplonemids and kinetoplastids. The phylogenetic position of the diplonemids within this phylum remains unsettled, since both morphological and molecular data produce weak and contradictory results. It is shown here that taxonomic sampling, G+C content bias, mutational saturation and differences of evolutionary rate among lineages are major factors affecting the topology of the small-subunit rRNA euglenozoan tree. When these problems are minimized by using a larger diplonemid sampling (including a sequence of environmental origin) and correcting for G+C bias (by using both paralinear distances or an unbiased dataset), a diplonemids+euglenoids sisterhood is retrieved. Bootstrap support for this relationship is still moderate, but it is retrieved by all analysis methods, overcoming previously reported disagreements. In addition, the inclusion of a large number of euglenoid sequences in the analysis improves some phylogenetic relationships within this group. Some problematic taxa, such as the species Khawkinea quartana, are now placed with high bootstrap support and monophyly is found for two interesting groups (the photosynthetic genera Eutreptia+Eutreptiella and the loricate genera Strombomonas+Trachelomonas), although with weak statistical support.

PMID:
11760964
DOI:
10.1099/00207713-51-6-2211
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Ingenta plc
Loading ...
Support Center