Additional taxonomic coverage of the doubly uniparental inheritance in bivalves: Evidence of sex‐linked heteroplasmy in the razor clam Solen marginatus Pulteney, 1799, but not in the lagoon cockle Cerastoderma glaucum (Bruguière, 1789)

Do not sacrifice the snail-conservative DNA extraction for terrestrial gastropods based on periostracum fraction and pedal mucus

Tissue collection methods for sampling of biological material often present various drawbacks related to ethical concerns as well as to the conservation status of many species. In this study, a conservative noninvasive sampling technique for genetic analyses was developed and optimized in three terrestrial gastropod species, namely, Cornu aspersum, Eobania vermiculata, and Helix lucorum. Our approach involves the sampling of a minimal amount of periosteum and pedal mucus, providing a viable alternative that does not harm the organisms, combining a few modifications in DNA isolation procedures depending on the sample. Mitochondrial CO1 and 18S rRNA genes were successfully amplified from both pedal mucus and periostracum samples, as confirmed by sequencing and BLAST comparisons in GenBank database. Interestingly, among the different sample types, shell from dead individuals demonstrated the highest DNA purity and quantity, likely due to the lack of DNA binding. This nondestructive method provides a promising advancement for conservation genetics, allowing for the study of protected species while maintaining their survival and well-being. The results demonstrate that this technique is an efficient and ethically sound tool for genetic studies, with potential applications in biodiversity monitoring and conservation research.

The gender-specific impact of starvation on mitotypes diversity in adults of Drosophila melanogaster

In animals, starvation can increase the level of reactive oxygen species (ROS) in some tissues. Mitochondrial DNA (mtDNA) is more vulnerable to being attacked by ROS due to the lack of histone protection, leading to oxidative damage. However, whether starvation is associated with the genetic diversity of mtDNA remains unclear. Here, by using adult individuals of Drosophila melanogaster under three different feeding treatments (starvation, with the provision of only water, and normal feeding), based on the high-throughput sequencing results of the PCR amplicons of the partial sequences of the mitochondrial gene cytochrome c oxidase subunit I (mt-cox1), no significant difference in the mean number of mitochondrial haplotypes and the mean genetic distance of haplotypes within individuals were identified between the three treatment groups. Coupled with the low proportion of heterogeneous mt-cox1 sequences within each individual, it suggested that starvation had a limited impact on mitotype genetic diversity and mitochondrial function. Nevertheless, starvation could significantly increase the sequence number of haplotypes containing specific mutations, and for males with higher levels of mitochondrial heteroplasmy than females in the normal feeding group, starvation could further increase their mitochondrial heteroplasmy.

No evidence of DUI in the Mediterranean alien species Brachidontes pharaonis (P. Fisher, 1870) despite mitochondrial heteroplasmy

Two genetically different mitochondrial haplogroups of Brachidontes pharaonis (p-distance 6.8%) have been identified in the Mediterranean Sea. This hinted at a possible presence of doubly uniparental inheritance in this species. To ascertain this possibility, we sequenced two complete mitogenomes of Brachidontes pharaonis mussels and performed a qPCR analysis to measure the relative mitogenome copy numbers of both mtDNAs. Despite the presence of two very similar regions composed entirely of repetitive sequences in the two haplogroups, no recombination between mitogenomes was detected. In heteroplasmic individuals, both mitogenomes were present in the generative tissues of both sexes, which argues against the presence of doubly uniparental inheritance in this species.