Researchers Discovered A Genetic Switch Called Foxl3 That Determines Whether Germ Cells Will Develop Into Sperm Or Egg Cells

Researchers from Japan’s National Institute for Basic Biology have discovered a Genetic Switch in vertebrates called Foxl3 that determines whether germ cells will develop into sperm or egg cells.

Germ cells are the cells needed for creating reproductive cells and are found only in organs or gonads where gametes are made, such as the ovaries in females and the testes in males. Depending on the gonads where they come from, they can either be sperm or egg cells. Foxl3 turned out to be the one that determines what will be produced.

The molecular mechanism that proves how germ cells transform into sperm or eggs has always been unclear until Dr. Toshiya Nishimura from Japan’s National Institute for Basic Biology and colleagues from the National Institutes of Natural Sciences in Japan discovered Foxl3 in small fish called Medaka (Oryzias latipes).

Foxl3 is basically active in germ cells in females, according to a study published in the journal Science and acts to prevent female germ cells from transforming into sperm and allowing the production of egg cells in the ovaries. In a female fish, when the researchers deactivated foxl3, sperm cells were produced in the ovaries. The sperm produced in the ovaries of female Medaka functioned normally and was successful in fertilizing eggs and produced healthy, normal offspring.

Minoru Tanaka Associate Professor of the National Institutes of Natural Sciences in Japan said “While germ cells can become either sperm or eggs, nobody knew that in vertebrates the germ cells have a switch mechanism to decide their own sperm or egg fate. Our result indicates that once the decision is made the germ cells have the ability to go all the way to the end. I believe it is of very large significance that this mechanism has been found.”

Dr. Toshiya Nishimura said “In spite of the environment surrounding the germ cells being female, the fact that functional sperm has been made surprised me greatly. That this sexual switch present in the germ cells is independent of the body’s sex is an entirely new finding.”

These female fish can produce sperm in less time that can help commercial fisheries to raise females to produce sperm for reproduction.

Although, Foxl3 gene is not possessed by humans, researchers believe that humans also have a similar genetic code found in their biological structures that can carry out the same process.