A research group led by Professor Akihisa Terakita of Osaka City University conducted research using fish, and found that two genes involved in "discrimination of light color" and "regulation of biological rhythm by light" were differentiated in the process of evolution. I found it to be a relationship.These have functions other than vision while having the function of sensing light, and are likely to be the key to elucidating how animals, including humans, acquired the non-visual sense of light.
Receptors that sense light are divided into those related to vision and those that do not.Evolutionary processes and functions of visual receptors have been elucidated at the genetic level, but little is known about non-visual receptors.To investigate this, the research group uses light to secrete a hormone called melatonin, which regulates biological rhythms, in the pineal gland in the brains of lower vertebrates such as fish, and in addition, it also distinguishes colors. I paid attention to.
First, we used a small fish called zebrafish to find out which of the many light-sensing proteins is involved in the regulation of melatonin.Furthermore, by analyzing the genes of various fish, we investigated in which process of evolution this gene was acquired.It was clarified that it was differentiated from the gene involved in the identification of light color by a phenomenon called "genome doubling" that occurred in fish about 3 million years ago.
Our findings indicate that genetic differentiation of photoreceptive proteins played an important role in acquiring the ability to regulate melatonin secretion by light.This is the first example of a previously unknown relationship between the origin and function of non-visual photoreceptive proteins.In the future, it is expected to be a great stepping stone in elucidating the functions of non-visual proteins and their evolutionary processes.
Source:[Osaka City University] Discovered twin genes that are the key to elucidating the evolution of light sensation in the pineal gland of fish