Mitochondrial Genomes of two Lycosa spiders (Araneae, Lycosidae): Genome Description and Phylogenetic Implications

Abstract

We sequenced the complete mitochondrial genomes of Lycosa shansia, and Lycosa singoriensis by combining Sanger and next-generation sequencing methods and analyzed the sequenced genomes in order to explore the phylogenetic placement and the mitogenome composition and evolution of these species. The mitochondrial genome of L. shansia was 14,638 bp, whereas that of L. singoriensis was 13,686 bp. The type of genes and direction of the coding strand present in the mitogenomes were the same as those in other species of Lycosoidea, including two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and 13 protein-coding genes (PCGs). The mitogenomes of the two species exhibited negative AT and positive GC skews. This indicated that the nucleotide compositions of the mitogenomes of L. singoriensis and L. shansia tended to be T and G. Both the mean and median values of Ka/Ks of ATP8 were the highest among the 13 protein-coding genes, indicating that it might have evolved more rapidly than the other protein-coding genes in both species. ATP8 may have undergone more relaxed selection constraints and accumulated more mutations. In addition, many tRNAs lacked T and D stem loops; a few had no acceptor stems. The assessed species were recovered nested within Lycosidae with high support. The present findings will be useful for future studies on the mitogenome evolution of spiders.

The complete mitochondrial genome of Pardosa pusiola (Araneae, Lycosidae) and its phylogenetic implications

“…According to the genomic data of prior research, the phylogenetic relationship of Thomisidae, Oxyopidae, Pisauridae, and Lycosidae could be presented as ((Thomisidae + Oxyopidae) + (Pisauridae + Lycosidae)) (Fernández et al 2018). However, our findings showed that the phylogenetic relationship was presented as (Thomisidae + (Oxyopidae + (Pisauridae + Lycosidae))), which is supported by numerous studies (Li et al 2021; Pons et al 2019; Ye et al 2022). Within Lycosidae, the phylogenetic relationships of three spiders were presented as ( Pirata subpiraticus + ( P. pusiola + P. laura )).…”

“…Within Lycosidae, the phylogenetic relationships of three spiders were presented as ( Pirata subpiraticus + ( P. pusiola + P. laura )). These results are well supported by previous spider phylogenetic research and reveal that the mitogenome is a useful tool for uncovering the phylogenetic relationships of spiders (Wheeler et al 2017; Ye et al 2022).…”

“…The overlap between atp6 and atp8 was considered a common feature among metazoan mitogenomes (Campbell & Barker 1999; Zhu et al 2019), and it also occurred in the P. pusiola mitogenome. Despite this region, overlaps and intergenic spaces are varied in their locations and sizes among arthropod mitogenomes (Xu et al 2019; Ye et al 2022; Zhang et al 2016).…”

“…On the other hand, three termination codons occurred in the P. pusiola mitogenome, including TAA ( atp6 , atp8 , nad3 , nad6 , cytb , and nad1 ), TAG ( nad2 , cox2 , and cox3 ) and the incomplete T ( cox1 , nad4 , nad4l , and nad5 ). These termination codons were common in mitogenomes of spiders, such as Desis jiaxiangi (Li et al 2021), Lycosa shansia (Ye et al 2022), and Tetragnatha maxillosa (Wang et al 2016). It has been suggested that the incomplete stop codon partly reflects the reduction of genome size under selective pressure and may be completed by posttranscriptional polyadenylation (Ojala et al 1981; Rand 1993).…”

“…It may be the most variable part of mitogenomes. For instance, the CR of L. shansia mitogenome is 984 bp, which is much longer than that in Lycosa singoriensis mitogenome (72 bp) (Ye et al 2022). The CRs of Nephila pilipes , Trichonephila antipodiana , and N. nautica are 498,428 and 455 bp, respectively (Wang et al 2016; Yong et al 2021).…”