ABSTRACT
The complete mitochondrial genome sequence of the Babylonia areolata was determined using PCR-based method. The total length of the mitogenome is 15,356 bp, including 2 ribosomal RNA genes, 13 protein-coding genes, 22 transfer RNA genes. The overall composition of the mitogenome was estimated to be 29.31% for A, 37.41% for T, 16.59% for C, and 16.70% for G, respectively, indicating that an A + T (66.72%)-rich feature occurs in the Babylonia areolata mitogenome.
Subject(s)
Gastropoda/genetics , Genome, Mitochondrial/genetics , Sequence Analysis, DNA , Animals , Genes, rRNA/genetics , Molecular Sequence Annotation , Molecular Sequence Data , Open Reading Frames/genetics , RNA, Transfer/geneticsABSTRACT
Peanut worm (Sipunculus nudus) is a cosmopolitan species mainly distributed in tropical and subtropical coastal waters. Analysis of the mitochondrial cytochrome c oxidase subunit I (COI) gene sequences among S. nudus from GenBank revealed high genetic variation (p-distance, 0.115-0.235; k2p, 0.128-0.297) and paraphyletic relationships. These indicated misidentification and/or cryptic diversity may be present in the genus Sipunculus. To understand the genetic diversity and to manage the recourse of S. nudus, we collected specimens from coastal waters of southern China and Taiwan. In the phylogenetic topology, specimens can be separated into four distinct clades; three of these clades (clade A, B and C) were only represented from this region (southern China and Taiwan), but the clade D grouped with individuals from Central America (Atlantic coast). Furthermore, individuals of clades A and D were collected at the same location, which does not support the hypothesis that this genetic break reflects contemporary geographical isolation. The four distinct clades observed among coastal waters of southern China and Taiwan indicated underestimated diversity. It is noteworthy that the cryptic diversity is vulnerable under high pressure of human activity.
