This time, research teams from Osaka City University, Osaka Prefecture University, Tohoku University, etc. have discovered that the deciduous tree "Lindera glauca", which is distributed all over Japan, is a huge clone derived from a single female strain.Lindera glauca is distributed in a range of more than 1 km in a straight line in Japan, and such a large-scale clone is extremely rare in the world.

　Although male and female strains of Lindera glauca grow on the continent, only female strains have been found in Japan, and female strains produce seeds by parthenogenesis without receiving pollen.The research team collected samples of the parent tree and seeds of Lindera glauca from Tohoku (Miyagi) to Kyushu (Kumamoto), and analyzed the DNA information using a next-generation sequencer. Not only that, we found that there were few mutations among the samples throughout Japan.This means that all Lindera glauca in Japan are clones with the same gene.

　On the other hand, the three dioecious tree species Abrachan, Kuro-moji, and Lindera obtusiloba, which are closely related to Lindera glauca, have both male and female strains growing in Japan, and self-fertilization and parthenogenesis were performed in the same survey. However, it was found that dioecious mating always avoids inbreeding depression.

　Thus, dioecious plants may compensate for the disadvantages of dioeciousness by avoiding inbreeding depression, such as Abrachan, while they have the advantage of producing seeds alone, such as Lindera glauca. It was shown that he has various ways of life, such as having acquired it.

　These achievements may also lead to the elucidation of the reason why the system of sex is widespread in the world of living things.

Paper information:[Forests] Genetic diversity and structure of apomictic and sexually reproducing Linderaspecies (Lauraceae) in Japan