A transcriptomic-phylogenomic analysis of the evolutionary relationships of flatworms.

Details

Serval ID
serval:BIB_79C6402C984D
Type
Article: article from journal or magazin.
Collection
Publications
Title
A transcriptomic-phylogenomic analysis of the evolutionary relationships of flatworms.
Journal
Current Biology
Author(s)
Egger B., Lapraz F., Tomiczek B., Müller S., Dessimoz C., Girstmair J., Škunca N., Rawlinson K.A., Cameron C.B., Beli E., Todaro M.A., Gammoudi M., Noreña C., Telford M.J.
ISSN
1879-0445 (Electronic)
ISSN-L
0960-9822
Publication state
Published
Issued date
2015
Volume
25
Number
10
Pages
1347-1353
Language
english
Abstract
The interrelationships of the flatworms (phylum Platyhelminthes) are poorly resolved despite decades of morphological and molecular phylogenetic studies. The earliest-branching clades (Catenulida, Macrostomorpha, and Polycladida) share spiral cleavage and entolecithal eggs with other lophotrochozoans. Lecithoepitheliata have primitive spiral cleavage but derived ectolecithal eggs. Other orders (Rhabdocoela, Proseriata, Tricladida and relatives, and Bothrioplanida) all have derived ectolecithal eggs but have uncertain affinities to one another. The orders of parasitic Neodermata emerge from an uncertain position from within these ectolecithal classes. To tackle these problems, we have sequenced transcriptomes from 18 flatworms and 5 other metazoan groups. The addition of published data produces an alignment of >107,000 amino acids with less than 28% missing data from 27 flatworm taxa in 11 orders covering all major clades. Our phylogenetic analyses show that Platyhelminthes consist of the two clades Catenulida and Rhabditophora. Within Rhabditophora, we show the earliest-emerging branch is Macrostomorpha, not Polycladida. We show Lecithoepitheliata are not members of Neoophora but are sister group of Polycladida, implying independent origins of the ectolecithal eggs found in Lecithoepitheliata and Neoophora. We resolve Rhabdocoela as the most basally branching euneoophoran taxon. Tricladida, Bothrioplanida, and Neodermata constitute a group that appears to have lost both spiral cleavage and centrosomes. We identify Bothrioplanida as the long-sought closest free-living sister group of the parasitic Neodermata. Among parasitic orders, we show that Cestoda are closer to Trematoda than to Monogenea, rejecting the concept of the Cercomeromorpha. Our results have important implications for understanding the evolution of this major phylum.
Keywords
Animals, Biological Evolution, Centromere/genetics, Female, Gene Expression Profiling, Male, Ovum/physiology, Phylogeny, Planarians/genetics, Platyhelminths/genetics, Platyhelminths/physiology, Spermatozoa/physiology, Terminology as Topic
Pubmed
Web of science
Open Access
Yes
Create date
06/07/2016 9:23
Last modification date
20/08/2019 14:36
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