Genetic diversity and population structure of the Asian green mussel Perna viridis in South China Sea based on microsatellite markers

Population connectivity and genetic structure of Asian green mussel, Perna viridis along Indian waters assessed using mitochondrial markers

Perna viridis (Linnaeus, 1758), the Asian green mussel, belonging to the family Mytilidae is widely distributed along the Indian coast. The species is majorly found in southeastern countries and is considered an ideal candidate for aquaculture due to its high nutritional value and growth rate. Obtaining their genetic information is essential for their sustainable capture-based production. In the present study, genetic variation, population structure, and demographic processes of the populations across the distribution of this species were assessed using the mitochondrial DNA ATPase6 and cytb gene. In total, we selected 170 samples from five localities across the Indian subcontinent including Andaman Sea. Sequence analysis of partial cytb (885 bp) and ATPase6 (714 bp) genes revealed 45 and 58 haplotypes, respectively. The significant coefficient of genetic differentiation (F_ST: 0.255 for cytb and 0.252 for ATPase6) and analyses of molecular variance indicated three varieties of stocks, namely Arabian Sea, Bay of Bengal, and Andaman Sea. All the populations showed low nucleotide diversity, suggesting severe historical bottleneck events and high haplotype diversity, indicating population expansion. The genetic variation and demographic process reported in this study will form the baseline information for framing policies, which can be adopted while planning stock specific ranching and relaying programmes in the Indian subcontinent with view to enhance and manage the fishery.

Population genetic structure and phylogenetic analysis of gray's pipefish, Halicampus grayi in the South China Sea

BACKGROUND

The evolution of male pregnancy is the most distinctive characteristic of syngnathids, and they were recognized as flagship species for marine conservation. Genus Halicampus is an important branch of syngnathid fishes that has not received the attention it deserves.

OBJECTIVE

To sequence the mitochondrial genome of Halicampus grayi, and investage the genetic structure of its populations.

METHODS

Degenerate primers were designed to amplify the entire mitochondrial genome of H. grayi. The phylogenetic relationship between H. grayi and other syngnathids were conducted using maximum-likelihood method. Population genetic structure of three geographic population of H. grayi were determined using median-joining haplotype network based on COI and Cytb sequences.

RESULTS

The complete mitochondrial genome of Halicampus grayi was assembled into a 17,059 bp circular sequence, which contains 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and 1 D-loop region. The overall base composition of H. grayi is 29.93% A, 29.31% T, 16.23% G and 24.54% C, with a slight A + T rich feature (59.24%). Phylogenetic analysis indicated that H. grayi has a close relationship with Trachyrhamphus serratus. Population genetic analysis revealed a relatively high genetic diversity across different geographic populations of H. grayi, and the results of median-joining haplotype network indicated a lack of structure in populations of H. grayi.

CONCLUSION

The mitogenome of H. grayi will provided important information about the origin and evolution issues of syngnathid fishes, and the high-level genetic diversity detected in their populations will provide insight into the gene flow pattern of marine fishes.