An EST screen from the annelid Pomatoceros lamarckii reveals patterns of gene loss and gain in animals

Takahashi, Tokiharu, McDougall, Carmel, Troscianko, Jolyon, Chen, Wei-Chung, Jayaraman-Nagarajan, Ahamarshan, Shimeld, Sebastian M. and Ferrier, David E. K. (2009) An EST screen from the annelid Pomatoceros lamarckii reveals patterns of gene loss and gain in animals. BMC Evolutionary Biology, 9 1: Article number 240. doi:10.1186/1471-2148-9-240


Author Takahashi, Tokiharu
McDougall, Carmel
Troscianko, Jolyon
Chen, Wei-Chung
Jayaraman-Nagarajan, Ahamarshan
Shimeld, Sebastian M.
Ferrier, David E. K.
Title An EST screen from the annelid Pomatoceros lamarckii reveals patterns of gene loss and gain in animals
Journal name BMC Evolutionary Biology   Check publisher's open access policy
ISSN 1471-2148
Publication date 2009-09
Sub-type Article (original research)
DOI 10.1186/1471-2148-9-240
Open Access Status DOI
Volume 9
Issue 1
Start page Article number 240
Total pages 17
Editor M. Norton
Place of publication London, United Kingdom
Publisher Biomed Central
Collection year 2010
Language eng
Subject 0604 Genetics
0603 Evolutionary Biology
Formatted abstract
Background
Since the drastic reorganisation of the phylogeny of the animal kingdom into three major clades of bilaterians; Ecdysozoa, Lophotrochozoa and Deuterostomia, it became glaringly obvious that the selection of model systems with extensive molecular resources was heavily biased towards only two of these three clades, namely the Ecdysozoa and Deuterostomia. Increasing efforts have been put towards redressing this imbalance in recent years, and one of the principal phyla in the vanguard of this endeavour is the Annelida.

Results

In the context of this effort we here report our characterisation of an Expressed Sequence Tag (EST) screen in the serpulid annelid, Pomatoceros lamarckii. We have sequenced over 5,000 ESTs which consolidate into over 2,000 sequences (clusters and singletons). These sequences are used to build phylogenetic trees to estimate relative branch lengths amongst different taxa and, by comparison to genomic data from other animals, patterns of gene retention and loss are deduced.

Conclusion

The molecular phylogenetic trees including the P. lamarckii sequences extend early observations that polychaetes tend to have relatively short branches in such trees, and hence are useful taxa with which to reconstruct gene family evolution. Also, with the availability of lophotrochozoan data such as that of P. lamarckii, it is now possible to make much more accurate reconstructions of the gene complement of the ancestor of the bilaterians than was previously possible from comparisons of ecdysozoan and deuterostome genomes to non-bilaterian outgroups. It is clear that the traditional molecular model systems for protostomes (e.g. Drosophila melanogaster and Caenorhabditis elegans), which are restricted to the Ecdysozoa, have undergone extensive gene loss during evolution. These ecdysozoan systems, in terms of gene content, are thus more derived from the bilaterian ancestral condition than lophotrochozoan systems like the polychaetes, and thus cannot be used as good, general representatives of protostome genomes. Currently sequenced insect and nematode genomes are less suitable models for deducing bilaterian ancestral states than lophotrochozoan genomes, despite the array of powerful genetic and mechanistic manipulation techniques in these ecdysozoans. A distinct category of genes that includes those present in non-bilaterians and lophotrochozoans, but which are absent from ecdysozoans and deuterostomes, highlights the need for further lophotrochozoan data to gain a more complete understanding of the gene complement of the bilaterian ancestor.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2010 Higher Education Research Data Collection
School of Biological Sciences Publications
 
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Citation counts: TR Web of Science Citation Count  Cited 22 times in Thomson Reuters Web of Science Article | Citations
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Created: Thu, 12 Nov 2009, 11:54:38 EST by Mr Andrew Martlew on behalf of School of Biological Sciences