International Journal of Aquaculture, 2025, Vol.15, No.4, 197-207 http://www.aquapublisher.com/index.php/ija 204 the environment. This phenomenon is more clear in plants, and it has also begun to attract attention in invertebrates such as oysters. Studies have shown that some environmentally induced epigenetic changes can be maintained over the course of oyster life and are not completely cleared when gametes form, thus passing on to the next generation (Figure 2) (Li et al., 2022). There were experiments that exposed parental oysters to low salt or high CO₂ stress, and then observed the phenotype of their offspring. It was found that the offspring born to parents who received stress treatment had a high survival rate under the corresponding stress conditions and showed some kind of "pre-adaptation" ability (Venkataraman et al., 2020). This suggests that oysters may have epigenetic memory mechanisms that transmit information from parental experiences through epitaphs coded in germ cells. DNA methylation is considered one of the vectors of this memory, as invertebrates such as oysters may not completely erase the methylation map of the parent during gametogenesis compared to mammals. Several sensitive molecular tests have found that the presence of specific methylation and ncRNA markers in oyster sperm and egg cells is associated with the parental environment. Studies have found that even if the pesticide dichloron is not exposed, the offspring of oysters has characteristic changes related to parental treatment on the DNA methylation map, and these changes are concentrated on development-related genes. Figure 2 Transcriptional regulation of the cell cycle and DNA replication in eastern oysters under stress (Adopted from Li et al., 2022) Image caption: The gene names are the following: CDC, cell division cycle-related protein kinase; CDK, cyclin-dependent kinase; E2F, transcription factor E2F3; GADD 45, growth arrest and DNA damage-inducible protein 45; MCM2-7, minichromosome maintenance proteins; PCNA, proliferating cell nuclear antigen; RFC, replication factor C; RPA, replication protein A (Adopted from Li et al., 2022) 6.3 Long-term impact of environmental changes on the adaptability of oyster populations From a population and evolutionary perspective, environmentally driven epigenetic variation may be an important source of adaptation to environmental changes in oyster populations. Traditional concepts believe that adaptation mainly depends on natural selection of DNA sequence mutations, but recent studies have found that epigenetic mutations tend to be faster and more reversible, and may play a greater role in short-term adaptation. Johnson and
RkJQdWJsaXNoZXIy MjQ4ODYzNA==