Phylogenetic position of a whale-fall lancelet (Cephalochordata) inferred from whole mitochondrial genome sequences
Abstract Background The lancelet Asymmetron inferum (subphylum Cephalochordata) was recently discovered on the ocean floor off the southwest coast of Japan at a depth of 229 m, in an anaerobic and sulfide-rich environment caused by decomposing bodies of the sperm whale Physeter macrocephalus . This...
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ftdoajarticles:oai:doaj.org/article:849775a1a71547b5b5fd154204bf1178 2023-05-15T17:59:27+02:00 Phylogenetic position of a whale-fall lancelet (Cephalochordata) inferred from whole mitochondrial genome sequences Nishida Mutsumi Fujiwara Yoshihiro Yamanoue Yusuke Nohara Masahiro Kon Takeshi Nishikawa Teruaki 2007-07-01T00:00:00Z https://doi.org/10.1186/1471-2148-7-127 https://doaj.org/article/849775a1a71547b5b5fd154204bf1178 EN eng BMC http://www.biomedcentral.com/1471-2148/7/127 https://doaj.org/toc/1471-2148 doi:10.1186/1471-2148-7-127 1471-2148 https://doaj.org/article/849775a1a71547b5b5fd154204bf1178 BMC Evolutionary Biology, Vol 7, Iss 1, p 127 (2007) Evolution QH359-425 article 2007 ftdoajarticles https://doi.org/10.1186/1471-2148-7-127 2022-12-31T04:54:09Z Abstract Background The lancelet Asymmetron inferum (subphylum Cephalochordata) was recently discovered on the ocean floor off the southwest coast of Japan at a depth of 229 m, in an anaerobic and sulfide-rich environment caused by decomposing bodies of the sperm whale Physeter macrocephalus . This deep sulfide-rich habitat of A. inferum is unique among the lancelets. The distinguishing adaptation of this species to such an extraordinary habitat can be considered in a phylogenetic framework. As the first step of reconstruction of the evolutionary processes in this species, we investigated its phylogenetic position based on 11 whole mitochondrial genome sequences including the newly determined ones of the whale-fall lancelet A. inferum and two coral-reef congeners. Results Our phylogenetic analyses showed that extant lancelets are clustered into two major clades, the Asymmetron clade and the Epigonichthys + Branchiostoma clade. A. inferum was in the former and placed in the sister group to A. lucayanum complex. The divergence time between A. inferum and A. lucayanum complex was estimated to be 115 Mya using the penalized likelihood (PL) method or 97 Mya using the nonparametric rate smoothing (NPRS) method (the middle Cretaceous). These are far older than the first appearance of large whales (the middle Eocene, 40 Mya). We also discovered that A. inferum mitogenome (mitochondrial genome) has been subjected to large-scale gene rearrangements, one feature of rearrangements being unique among the lancelets and two features shared with A. lucayanum complex. Conclusion Our study supports the monophyly of genus Asymmetron assumed on the basis of the morphological characters. Furthermore, the features of the A. inferum mitogenome expand our knowledge of variation within cephalochordate mitogenomes, adding a new case of transposition and inversion of the trnQ gene. Our divergence time estimation suggests that A. inferum remained a member of the Mesozoic and the early Cenozoic large vertebrate-fall communities before ... Article in Journal/Newspaper Physeter macrocephalus Sperm whale Directory of Open Access Journals: DOAJ Articles BMC Evolutionary Biology 7 1 127 |
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Evolution QH359-425 |
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Evolution QH359-425 Nishida Mutsumi Fujiwara Yoshihiro Yamanoue Yusuke Nohara Masahiro Kon Takeshi Nishikawa Teruaki Phylogenetic position of a whale-fall lancelet (Cephalochordata) inferred from whole mitochondrial genome sequences |
topic_facet |
Evolution QH359-425 |
description |
Abstract Background The lancelet Asymmetron inferum (subphylum Cephalochordata) was recently discovered on the ocean floor off the southwest coast of Japan at a depth of 229 m, in an anaerobic and sulfide-rich environment caused by decomposing bodies of the sperm whale Physeter macrocephalus . This deep sulfide-rich habitat of A. inferum is unique among the lancelets. The distinguishing adaptation of this species to such an extraordinary habitat can be considered in a phylogenetic framework. As the first step of reconstruction of the evolutionary processes in this species, we investigated its phylogenetic position based on 11 whole mitochondrial genome sequences including the newly determined ones of the whale-fall lancelet A. inferum and two coral-reef congeners. Results Our phylogenetic analyses showed that extant lancelets are clustered into two major clades, the Asymmetron clade and the Epigonichthys + Branchiostoma clade. A. inferum was in the former and placed in the sister group to A. lucayanum complex. The divergence time between A. inferum and A. lucayanum complex was estimated to be 115 Mya using the penalized likelihood (PL) method or 97 Mya using the nonparametric rate smoothing (NPRS) method (the middle Cretaceous). These are far older than the first appearance of large whales (the middle Eocene, 40 Mya). We also discovered that A. inferum mitogenome (mitochondrial genome) has been subjected to large-scale gene rearrangements, one feature of rearrangements being unique among the lancelets and two features shared with A. lucayanum complex. Conclusion Our study supports the monophyly of genus Asymmetron assumed on the basis of the morphological characters. Furthermore, the features of the A. inferum mitogenome expand our knowledge of variation within cephalochordate mitogenomes, adding a new case of transposition and inversion of the trnQ gene. Our divergence time estimation suggests that A. inferum remained a member of the Mesozoic and the early Cenozoic large vertebrate-fall communities before ... |
format |
Article in Journal/Newspaper |
author |
Nishida Mutsumi Fujiwara Yoshihiro Yamanoue Yusuke Nohara Masahiro Kon Takeshi Nishikawa Teruaki |
author_facet |
Nishida Mutsumi Fujiwara Yoshihiro Yamanoue Yusuke Nohara Masahiro Kon Takeshi Nishikawa Teruaki |
author_sort |
Nishida Mutsumi |
title |
Phylogenetic position of a whale-fall lancelet (Cephalochordata) inferred from whole mitochondrial genome sequences |
title_short |
Phylogenetic position of a whale-fall lancelet (Cephalochordata) inferred from whole mitochondrial genome sequences |
title_full |
Phylogenetic position of a whale-fall lancelet (Cephalochordata) inferred from whole mitochondrial genome sequences |
title_fullStr |
Phylogenetic position of a whale-fall lancelet (Cephalochordata) inferred from whole mitochondrial genome sequences |
title_full_unstemmed |
Phylogenetic position of a whale-fall lancelet (Cephalochordata) inferred from whole mitochondrial genome sequences |
title_sort |
phylogenetic position of a whale-fall lancelet (cephalochordata) inferred from whole mitochondrial genome sequences |
publisher |
BMC |
publishDate |
2007 |
url |
https://doi.org/10.1186/1471-2148-7-127 https://doaj.org/article/849775a1a71547b5b5fd154204bf1178 |
genre |
Physeter macrocephalus Sperm whale |
genre_facet |
Physeter macrocephalus Sperm whale |
op_source |
BMC Evolutionary Biology, Vol 7, Iss 1, p 127 (2007) |
op_relation |
http://www.biomedcentral.com/1471-2148/7/127 https://doaj.org/toc/1471-2148 doi:10.1186/1471-2148-7-127 1471-2148 https://doaj.org/article/849775a1a71547b5b5fd154204bf1178 |
op_doi |
https://doi.org/10.1186/1471-2148-7-127 |
container_title |
BMC Evolutionary Biology |
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7 |
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1 |
container_start_page |
127 |
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1766168273772085248 |