A close phylogenetic relationship between Sipuncula and Annelida evidenced from the complete mitochondrial genome sequence of <it>Phascolosoma esculenta</it>
<p>Abstract</p> <p>Background</p> <p>There are many advantages to the application of complete mitochondrial (mt) genomes in the accurate reconstruction of phylogenetic relationships in Metazoa. Although over one thousand metazoan genomes have been sequenced, the taxonom...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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BMC
2009-03-01
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| Series: | BMC Genomics |
| Online Access: | http://www.biomedcentral.com/1471-2164/10/136 |
| _version_ | 1818960215456874496 |
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| author | Ren Jianfeng Ma Xiaoyin Shen Xin Zhao Fangqing |
| author_facet | Ren Jianfeng Ma Xiaoyin Shen Xin Zhao Fangqing |
| author_sort | Ren Jianfeng |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>There are many advantages to the application of complete mitochondrial (mt) genomes in the accurate reconstruction of phylogenetic relationships in Metazoa. Although over one thousand metazoan genomes have been sequenced, the taxonomic sampling is highly biased, left with many phyla without a single representative of complete mitochondrial genome. Sipuncula (peanut worms or star worms) is a small taxon of worm-like marine organisms with an uncertain phylogenetic position. In this report, we present the mitochondrial genome sequence of <it>Phascolosoma esculenta</it>, the first complete mitochondrial genome of the phylum.</p> <p>Results</p> <p>The mitochondrial genome of <it>P</it>.<it>esculenta </it>is 15,494 bp in length. The coding strand consists of 32.1% A, 21.5% C, 13.0% G, and 33.4% T bases (AT = 65.5%; AT skew = -0.019; GC skew = -0.248). It contains thirteen protein-coding genes (PCGs) with 3,709 codons in total, twenty-two transfer RNA genes, two ribosomal RNA genes and a non-coding AT-rich region (AT = 74.2%). All of the 37 identified genes are transcribed from the same DNA strand. Compared with the typical set of metazoan mt genomes, sipunculid lacks <it>trnR </it>but has an additional <it>trnM</it>. Maximum Likelihood and Bayesian analyses of the protein sequences show that Myzostomida, Sipuncula and Annelida (including echiurans and pogonophorans) form a monophyletic group, which supports a closer relationship between Sipuncula and Annelida than with Mollusca, Brachiopoda, and some other lophotrochozoan groups.</p> <p>Conclusion</p> <p>This is the first report of a complete mitochondrial genome as a representative within the phylum Sipuncula. It shares many more similar features with the four known annelid and one echiuran mtDNAs. Firstly, sipunculans and annelids share quite similar gene order in the mitochondrial genome, with all 37 genes located on the same strand; secondly, phylogenetic analyses based on the concatenated protein sequences also strongly support the sipunculan + annelid clade (including echiurans and pogonophorans). Hence annelid "key-characters" including segmentation may be more labile than previously assumed.</p> |
| first_indexed | 2024-12-20T11:54:00Z |
| format | Article |
| id | doaj.art-4de4418f204040cb8eb87ab566bccb5a |
| institution | Directory Open Access Journal |
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| last_indexed | 2024-12-20T11:54:00Z |
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| spelling | doaj.art-4de4418f204040cb8eb87ab566bccb5a2022-12-21T19:41:43ZengBMCBMC Genomics1471-21642009-03-0110113610.1186/1471-2164-10-136A close phylogenetic relationship between Sipuncula and Annelida evidenced from the complete mitochondrial genome sequence of <it>Phascolosoma esculenta</it>Ren JianfengMa XiaoyinShen XinZhao Fangqing<p>Abstract</p> <p>Background</p> <p>There are many advantages to the application of complete mitochondrial (mt) genomes in the accurate reconstruction of phylogenetic relationships in Metazoa. Although over one thousand metazoan genomes have been sequenced, the taxonomic sampling is highly biased, left with many phyla without a single representative of complete mitochondrial genome. Sipuncula (peanut worms or star worms) is a small taxon of worm-like marine organisms with an uncertain phylogenetic position. In this report, we present the mitochondrial genome sequence of <it>Phascolosoma esculenta</it>, the first complete mitochondrial genome of the phylum.</p> <p>Results</p> <p>The mitochondrial genome of <it>P</it>.<it>esculenta </it>is 15,494 bp in length. The coding strand consists of 32.1% A, 21.5% C, 13.0% G, and 33.4% T bases (AT = 65.5%; AT skew = -0.019; GC skew = -0.248). It contains thirteen protein-coding genes (PCGs) with 3,709 codons in total, twenty-two transfer RNA genes, two ribosomal RNA genes and a non-coding AT-rich region (AT = 74.2%). All of the 37 identified genes are transcribed from the same DNA strand. Compared with the typical set of metazoan mt genomes, sipunculid lacks <it>trnR </it>but has an additional <it>trnM</it>. Maximum Likelihood and Bayesian analyses of the protein sequences show that Myzostomida, Sipuncula and Annelida (including echiurans and pogonophorans) form a monophyletic group, which supports a closer relationship between Sipuncula and Annelida than with Mollusca, Brachiopoda, and some other lophotrochozoan groups.</p> <p>Conclusion</p> <p>This is the first report of a complete mitochondrial genome as a representative within the phylum Sipuncula. It shares many more similar features with the four known annelid and one echiuran mtDNAs. Firstly, sipunculans and annelids share quite similar gene order in the mitochondrial genome, with all 37 genes located on the same strand; secondly, phylogenetic analyses based on the concatenated protein sequences also strongly support the sipunculan + annelid clade (including echiurans and pogonophorans). Hence annelid "key-characters" including segmentation may be more labile than previously assumed.</p>http://www.biomedcentral.com/1471-2164/10/136 |
| spellingShingle | Ren Jianfeng Ma Xiaoyin Shen Xin Zhao Fangqing A close phylogenetic relationship between Sipuncula and Annelida evidenced from the complete mitochondrial genome sequence of <it>Phascolosoma esculenta</it> BMC Genomics |
| title | A close phylogenetic relationship between Sipuncula and Annelida evidenced from the complete mitochondrial genome sequence of <it>Phascolosoma esculenta</it> |
| title_full | A close phylogenetic relationship between Sipuncula and Annelida evidenced from the complete mitochondrial genome sequence of <it>Phascolosoma esculenta</it> |
| title_fullStr | A close phylogenetic relationship between Sipuncula and Annelida evidenced from the complete mitochondrial genome sequence of <it>Phascolosoma esculenta</it> |
| title_full_unstemmed | A close phylogenetic relationship between Sipuncula and Annelida evidenced from the complete mitochondrial genome sequence of <it>Phascolosoma esculenta</it> |
| title_short | A close phylogenetic relationship between Sipuncula and Annelida evidenced from the complete mitochondrial genome sequence of <it>Phascolosoma esculenta</it> |
| title_sort | close phylogenetic relationship between sipuncula and annelida evidenced from the complete mitochondrial genome sequence of it phascolosoma esculenta it |
| url | http://www.biomedcentral.com/1471-2164/10/136 |
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