The complete mitochondrial genome of Octopus vulgaris.

BACKGROUND: The Octopus vulgaris species complex consists of numerous morphologically similar but genetically distinct species. The current publicly available mitogenome of this species has been generated from a specimen collected from Tsukiji Fish Market, Tokyo, Japan. Octopus from the northwestern Pacific Ocean are now considered to be a separate species, Octopus sinensis. For this reason, we hypothesised that the current record of O. vulgaris was sequenced from a specimen of O. sinensis. Here, we sequenced the first complete mitogenome of a specimen of Octopus vulgaris sensu stricto that was collected from the species' confirmed distribution areas in northeastern Atlantic. METHODS AND RESULTS: The complete mitogenome was assembled de novo and annotated using 250 bp paired-end sequences. A single circular contig 15,655 bp in length with a mean read coverage of 1089 reads was reconstructed. The annotation pipeline identified 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNA) and two ribosomal RNAs. A maximum likelihood phylogenetic tree recovered the assembled mitogenome as the sister taxon of a monophyletic group comprising O. sinensis and the previously published mitogenome of "O. vulgaris" from Japan. This confirms that the latter was a Japanese specimen of O. sinensis. CONCLUSION: The mitogenome sequenced here is the first to be published for Octopus vulgaris sensu stricto. It represents an important first step in genetics-informed research on the evolution, conservation, and management of this commercially important species.

The complete mitogenome dataset of the Critically Endangered estuarine pipefish, Syngnathus watermeyeri.

The Critically Endangered South African estuarine pipefish, Syngnathus watermeyeri, is one of the rarest teleost fish on the planet. In this analysed dataset, the complete mitochondrial genome of this species was assembled, annotated, and described. In addition, its evolutionary history was reconstructed in a Maximum Likelihood and a Bayesian framework. A circular mitochondrial contig 16 449 bp in length was assembled. A total of 13 protein-coding genes, 22 tRNAs and two rRNAs were annotated. The mitochondrial phylogenetic analysis showed that S. watermeyeri diverged from its widely distributed southern African sister species S. temminckii approximately 1.5 million years ago, and the ancestor of these two southern Afican pipefish species diverged from a clade of northern hemisphere pipefishes comprising S. acus, S. rostellatus, and S. typhle approximately 5.3 million years ago. The dataset presented here serves as the first step in understanding the evolutionary history of Africa's rarest pipefish.

Reconstruction of the complete mitogenomes of predator and prey from a faecal metagenomic dataset.

The application of faecal DNA in genetic studies of wild populations minimises disturbances to their normal behaviours and body integrity. Here, I present an analysis of a metagenomic dataset generated from the faecal DNA of several specimens of the estuarine pipefish, Syngnathus watermeyeri, to simultaneously assemble the mitogenomes of the predator and its main prey species, the copepod Pseudodiaptomus hessei. The mitogenomes of the pipefish and the copepod were successfully reconstructed using a combination of short seed extension and denovo metagenomic assembly. Nucleotide blast searches of the circular contigs, mitogenome annotations, and Bayesian phylogenetic analyses confirm the completeness and correct taxonomic placements of the two mitogenomes. In addition, heteroplasmy detection and Pool-Seq variant calling quantified the level of genetic diversity in the sequences that formed these assemblies. These can be used as a first step to non-invasively survey genetic diversity in these populations.

The effect of terrain on the fine-scale genetic diversity of sub-Antarctic Collembola: A landscape genetics approach.

Biodiversity patterns are shaped by the interplay between geodiversity and organismal characteristics. Superimposing genetic structure onto landscape heterogeneity (i.e., landscape genetics) can help to disentangle their interactions and better understand population dynamics. Previous studies on the sub-Antarctic Prince Edward Islands (located midway between Antarctica and Africa) have highlighted the importance of landscape and climatic barriers in shaping spatial genetic patterns and have drawn attention to the value of these islands as natural laboratories for studying fundamental concepts in biology. Here, we assessed the fine-scale spatial genetic structure of the springtail, Cryptopygus antarcticus travei, which is endemic to Marion Island, in tandem with high-resolution geological data. Using a species-specific suite of microsatellite markers, a fine-scale sampling design incorporating landscape complexity and generalised linear models (GLMs), we examined genetic patterns overlaid onto high-resolution digital surface models and surface geology data across two 1-km sampling transects. The GLMs revealed that genetic patterns across the landscape closely track landscape resistance data in concert with landscape discontinuities and barriers to gene flow identified at a scale of a few metres. These results show that the island's geodiversity plays an important role in shaping biodiversity patterns and intraspecific genetic diversity. This study illustrates that fine-scale genetic patterns in soil arthropods are markedly more structured than anticipated, given that previous studies have reported high levels of genetic diversity and evidence of genetic structing linked to landscape changes for springtail species and considering the homogeneity of the vegetation complexes characteristic of the island at the scale of tens to hundreds of metres. By incorporating fine-scale and high-resolution landscape features into our study, we were able to explain much of the observed spatial genetic patterns. Our study highlights geodiversity as a driver of spatial complexity. More widely, it holds important implications for the conservation and management of the sub-Antarctic islands.