鲸类<i>TRPA1</i>基因的进化差异及其在水生适应的潜在作用

Gene loss represents a powerful driver of adaptive evolution. Cetaceans, which underwent a profound transition from terrestrial to fully aquatic life, provide an excellent model for investigating this process. Comparative genomic analysis of the cold-sensitive ion channel transient receptor potential ankyrin 1 ( <i>TRPA1</i>) revealed lineage-specific patterns of degeneration across cetaceans. In toothed whales, the ancestral lineage exhibited extensive exon loss within the <i>TRPA1</i> locus, whereas baleen whales showed signatures consistent with markedly reduced or absent <i>TRPA1</i> expression. These molecular alterations were inferred to disrupt or abolish <i>TRPA1</i> protein function across cetaceans. Integration of these findings with established experimental evidence from human and murine TRPA1 studies supported several adaptive hypotheses for <i>TRPA1</i> gene loss, including tolerance to abrupt thermal fluctuations, attenuation of nociceptive responses in aquatic environments, specialization of integumentary sensory systems, and the emergence of echolocation-associated sensory trade-offs in toothed whales. Collectively, these findings expand the gene loss repertoire of cetaceans and provide novel insights into the molecular underpinnings of secondary aquatic adaptation in mammals.