Phylogenetic Position of Xenoturbella bocki and Hemichordates Balanoglossus carnosus and Saccoglossus kowalevskii Based on Amino Acid Composition or Nucleotide Content of Complete Mitochondrial Genomes

Kenji Sorimachi, Teiji Okayasu, Yoshifumi Ebara, Emiko Furuta, Shuji Ohhira

Abstract


To clarify the phylogenetic position of Xenoturbella bocki and hemichordates (Balanoglossus carnosus and Saccoglossus kowalevskii), which occupy an ambiguous evolutionary position between vertebrates and invertebrates, we expanded a pre-existing baseline vertebrate data set by incorporating randomly selected invertebrates. Based on nucleotide content calculated from complete mitochondrial genomes, invertebrates were classified into two groups, high C/G and low C/G, with vertebrates placed within the high-C/G invertebrate group. X. bocki and hemichordates (B. carnosus and S. kowalevskii) also fell into the high-C/G invertebrate group. We also analyzed amino acid composition and nucleotide content of complete mitochondrial genomes or 16S rRNA genes using Ward’s clustering method and neighbor-joining. In the resulting phylogenetic trees, invertebrates are classified into high C/G and low C/G categories, and vertebrates are divided into terrestrial and aquatic groups. In addition, X. bocki and representative hemichordates B. carnosus and S. kowalevskii appear to be more closely related to vertebrates than to invertebrates.


Full Text: PDF DOI: 10.5539/ijb.v6n1p82

Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.

International Journal of Biology   ISSN 1916-9671(Print)   ISSN 1916-968X  (Online)

Copyright © Canadian Center of Science and Education

To make sure that you can receive messages from us, please add the 'ccsenet.org' domain to your e-mail 'safe list'. If you do not receive e-mail in your 'inbox', check your 'bulk mail' or 'junk mail' folders.