Evolutionary Clues of North-South Divergence: Genomic Adaptation of the Intertidal Mudskipper Boleophthalmus pectinirostris

Boleophthalmus pectinirostris is an amphibious fish widely distributed in the coastal intertidal zone, which is a good object for evolutionary biology research. With the increasing application of whole-genome resequencing technology, genetic evolution analysis and gene screening can better clarify the genetic basis and molecular mechanisms of environmental adaptation. In the present study, B. pectinirostris samples were collected across five coastal regions of China, and their population genetic viarations, demographic history alteration, and environmental adaptation mechanisms were analyzed. After alignment with the reference genome, a total of 33,016,712 high-quality SNPs were obtained for 68 specimens. The results showed that population Qingdao (QD) exhibited strong genetic heterogeneity with other four populations, and its low genetic diversity may be related to its long-term population decline. The significant changes in the effective population size of different populations over history were revealed, with notable differences between northern and southern groups. In addition, Selective sweep analysis uncovered northern-adapted genes in B. pectinirostris, linked to energy metabolism and stress response under colder environments. The results of this study contribute to a better understanding of the adaptive evolution of intertidal fishes, particularly the mechanisms associated with temperature, seasonal fluctuations and other adaptations. These findings will provide an important scientific basis for the conservation and sustainable management of this species.