The freshwater fish "crucian carp", which is familiar to Japanese people, includes the usual "diploat that reproduces sexually in males and females (sexual crucian carp)" and "triple that reproduces clones only in females (clone crucian carp)". Exists.Clone crucian carp is a so-called "Gimbuna", and while it most commonly inhabits rivers and lakes all over Japan, sexual crucian carp includes Okinbuna and Nigorobuna, and coexists with Clone crucian carp.
Clone funa uses the male sperm of sexual funa only to stimulate egg development, and the offspring born from the egg carry out special clone reproduction (female development) in which the offspring become a clone of the female parent.Such cloned crucian carps inhabit not only Japan but also the Eurasian continent, but their origin is not clear, and despite being cloned breeding, genetic diversity is found among cloned crucian carps in various places. It was a mystery to be done.
A research group of Kyoto University, Tokai University, Ryukyu University, Nagasaki University and others conducted a detailed comparative analysis of the genes of about 1000 funa collected from all over Japan and the Eurasian Continent, and found the origin and genetic diversity of cloned funa. I found out the reason for having it.No genetic characteristics of Japanese sexual crucian carp were found in Eurasian cloned crucian carp, whereas Japanese cloned crucian carp was hybrid-like with both Japanese sexual and Eurasian crucian carp genetic characteristics. It is said that the heredity of the crucian carp was recognized.In particular, Japanese crucian carp had high genetic similarity to sexually resident crucian carp, so it is considered that there was a genetic exchange between crucian carp and sexual crucian carp in various places.
In other words, Japanese clone funa originally originated from the continent, and it is highly possible that they invaded Japan during the ice period when the Japanese archipelago and the continent were connected, and after that, they rarely crossed and reproduced with native sexual funa. It is presumed that it has evolved while acquiring new genes.
Evidence that cloned breeding organisms have taken up genes from sexual individuals is the first finding observed in vertebrates and is expected to provide clues to the sexual evolution of organisms.
Paper information:[Scientific Reports] Interploidy gene flow involving the sexual-asexual cycle facilitates the diversification of gynogenetic triploid Carassius fish