Bioethics News

Sperm from ovaries

This one’s a little technical, but may very well have significant implications for scientist’s ability to influence sex determination in mammals.

Japanese researchers have discovered a way to influence the sexual fate of germ cells in medaka (rice fish).

The Scientist reports:

“Somatic cells in the gonads of a developing vertebrate provide germ cells with cues, such as hormones, to develop into sperm or eggs. Studying the ways these cues affect a germ cell’s commitment to become sperm or eggs, Toshiya Nishimura from the laboratory of Minoru Tanaka at the National Institute for Basic Biology in Okazaki, Japan, and colleagues uncovered a single gene that, when missing from female embryos of the Japanese rice fish, or medaka (Oryzias latipes), leads the fish to produce functional sperm soon after hatching.”

According to the researchers, the gene foxl3, is the sole determinant in the sexual fate of the rice fish. Foxl3 appears to allow female germ cells to react to environmental signals while the mutant is shielded from these gonadal somatic cell cues. 

Researchers disrupted the foxl3 gene in some of the female specimens, and in these fish sperm began to generate in the ovaries. 

It’s unclear whether the results in medaka will have any impact on the study of sex determination in mammals, said Allan Spradling, a developmental biologist at the Carnegie Institution for Science in Baltimore, Maryland.

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