The complete mitochondrial genome of Sesarmops sinensis reveals gene rearrangements and phylogenetic relationships in Brachyura

Abstract

Mitochondrial genome (mitogenome) is very important to understand molecular evolution and phylogenetics. Herein, in this study, the complete mitogenome of Sesarmops sinensis was reported. The mitogenome was 15,905 bp in size, and contained 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a control region (CR). The AT skew and the GC skew are both negative in the mitogenomes of S. sinensis. The nucleotide composition of the S. sinensis mitogenome was also biased toward A + T nucleotides (75.7%). All tRNA genes displayed a typical mitochondrial tRNA cloverleaf structure, except for the trnS1 gene, which lacked a dihydroxyuridine arm. S. sinensis exhibits a novel rearrangement compared with the Pancrustacean ground pattern and other Brachyura species. Based on the 13 PCGs, the phylogenetic analysis showed that S. sinensis and Sesarma neglectum were clustered on one branch with high nodal support values, indicating that S. sinensis and S. neglectum have a sister group relationship. The group (S. sinensis + S. neglectum) was sister to (Parasesarmops tripectinis + Metopaulias depressus), suggesting that S. sinensis belongs to Grapsoidea, Sesarmidae. Phylogenetic trees based on amino acid sequences and nucleotide sequences of mitochondrial 13 PCGs using BI and ML respectively indicate that section Eubrachyura consists of four groups clearly. The resulting phylogeny supports the establishment of a separate subsection Potamoida. These four groups correspond to four subsections of Raninoida, Heterotremata, Potamoida, and Thoracotremata.

The complete mitochondrial genome of the freshwater crab Potamiscus motuoensis (Decapoda: Brachyura: Potamoidea)

“…The phylogenetic position of P. motuoensis in mitogenome relative to other Brachyuran mitogenomes is determined by applying the BI and ML methods on 13 PCGs (Figure 1). The results were consistent with the current molecular classification and morphological classification (Segawa and Aotsuka 2005;Liang 2013;Ming et al 2014;Tang et al 2017), with other freshwater crab species of family Potamoidea forming a separate clade.…”

A comprehensive phylogenetic analysis of Grapsoidea crabs (Decapoda: Brachyura) based on mitochondrial cytochrome oxidase subunit 1 (CO1) genes

“…Sesarma and Clistocoeloma are part of Sesarmidae, Grapsoidea. These findings are in keeping with previous reports (Von Hagen, 1978;Tang et al, 2017;Xin et al, 2017a) We present evidence that both Helice species are significantly closer to most Varunidae genera than to the Sesarmidae based on the CO1 genes sequences, which is in accordance with the findings reported by Guinot (1978) and Schubart et al ( , 2000. Preliminary results show that the genus Varuna clusters with the other Varunidae species based on its 16S rRNA sequence (Schubart et al, , 2000.…”

Comparative Mitochondrial Genome Analyses of Sesarmid and Other Brachyuran Crabs Reveal Gene Rearrangements and Phylogeny

“…The mitogenome composition (A: 36.61%, T: 38.20%, C: 15.13%, G: 10.06%) was strongly A + T biased which accounts for 74.81%, and exhibited with negative AT-skew (-0.021). The AT-skew of the mitogenomes of most crabs were negative, for example, H. wuana (Tang et al, 2018), S. sinensis (Tang et al, 2017), H. tientsinensis (Xin et al, 2017b), C. sinensis (Xin et al, 2017a), the AT-skew value of mitogenomes in other crabs had also been calculated and counted in related studies (Xin et al, 2017a,b). The genes were typical of animal mitogenomes, with 22 tRNA genes, 13 PCGs, 2 rRNA genes, and a CR ( Table 2).…”