The ‘genetic switch’ that is responsible for determining if a germ cell becomes sperm or eggs has been identified.
The National Institutes of Natural Sciences reported that a gene termed foxl3 was pinpointed in small medaka fish. In order to suppress differentiation of sperm, the researchers found the foxl3 gene works in the germ cells of females.
Without this gene being functional, medaka females in their ovaries produce sperm. These sperm function normally, and produce healthy offspring.
Researcher Toshiya Nishimura stated that “I have been surprised to see that in spite of the environment surrounding the germ cells being female, functional sperm has been made. This sexual switch present in the Germ Cells is independent of the body’s sex is an entirely new finding.”
Females that do not have foxl3 genes, which are functional, appear completely female, but a large number of sperm can be found in the ovaries along with a smaller number of eggs. The recent study found that for aquaculture, as compared to functioning males, females lacking the function of foxl3 functional sperm are easier to obtain.
Germ cells can become either sperm or eggs but until now no one was sure what the switch mechanism decided their fate. The findings indicate that once the decision is made the germ cells have the ability to go all the way to the end. The mechanism found is of significance.
Reproductive biologist Minoru Tanaka of Japan’s National Institute for Basic Biology added that “The germ cells were regarded as passive cells that are regulated by other cells.”
The findings have also opened up a new sphere of extensive research that is captivating scientists. The breakthrough could yield advances for genetic and reproductive research. The findings were published in a recent edition of the journal Science Express.