Conclusion
This study confirmed the existence of two genetically differentiated
populations that showed strong parallel evolution. Such genetic
parallelism was likely due to similar temperature environments. We
identified population-specific genes that may be related to adaptations
to high and low temperatures. These genes can be potential candidates
for further exploration of the underlying mechanisms involved in
confronting various challenges. In conclusion, by comparing the whole
genomes of S. japonica populations from environments with
different temperatures, we revealed various genes associated with local
adaptations of this species to cold- and high-temperature environments.
Specifically, the candidate genes were functionally related to membrane
fluidity in cold environments and the cytoskeleton
in high-temperature environments. These results advance our
understanding of the underlying genetic mechanisms that allow rapid
adaptations of fish species, particularly small ruminants, to survive in
extreme environments.