02833nas a2200301   4500008004100000020002300041245009000064210006900154260002700223300001600250490000700266520188800273100002002161700002202181700002602203700002002229700002502249700002402274700001902298700002302317700002802340700001602368700002002384700002102404700002202425700002702447856005702474       2015                        eng d  a0960-98221879-044500aA Transcriptomic-Phylogenomic Analysis of the Evolutionary Relationships of Flatworms0 aTranscriptomicPhylogenomic Analysis of the Evolutionary Relation  bCell Pressc2015/05/18  a1347 - 13530 v253 a<p>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 &gt;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&nbsp;Monogenea, rejecting the concept of the Cercomeromorpha. Our results have important implications for understanding the evolution of this major phylum.</p>
1 aEgger, Bernhard1 aLapraz, François1 aTomiczek, Bartłomiej1 aMüller, Steven1 aDessimoz, Christophe1 aGirstmair, Johannes1 aŠkunca, Nives1 aRawlinson, Kate, A1 aCameron, Christopher, B1 aBeli, Elena1 aTodaro, Antonio1 aGammoudi, Mehrez1 aNoreña, Carolina1 aTelford, Maximilian, J  uhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC4446793/