Abstract
Animals sense environmental temperatures and adapt via behavioral and physiological responses, therefore the thermoperceptions are likely to play crucial roles in adaptive evolution. The temperature receptors are the thermosensitive channels that belong to transient receptor potential (TRP) superfamily in animals. Since evolutionary changes of temperature-sensitive TRP channels directly alter the thermoperceptions, elucidation the evolutionary process of these genes is essential for understanding the adaptation to thermal environments. We collected the genes for temperature-sensitive TRP channels from the genome sequence databases of various vertebrates and conducted molecular phylogenetic analysis and estimated the evolutionary process. We showed that the most of the temperature-sensitive TRP channels were already existed in the ancestral vertebrates, while gene duplication and loss events occurred in the respective lineages resulted in the diversity of thermoTRP repertoires among species. In addition, to estimate the functional evolution, we cloned TRPV3 from western clawed frog belonging to amphibians that are phylogenetically distantly related to mammals and examined the functional properties by electrophysiological approaches. The temperature sensitivity of western clawed frog TRPV3 differed considerably from that of mammalian TRPV3, suggesting that temperature-sensitive TRP channels can dynamically change their functions through evolutionary process.
