Zebrafish

Danio rerio

Researchers in the Department of Chemistry at City University of Hong Kong found that when male zebrafish have a wounded heart, they secrete female sex hormones in order to speed up the recovery process. The increase in the female sex hormone was so great that the male zebrafish may begin to produce and egg yolk protein. Additionally, researchers found that if a male zebrafish was exposed to female hormones prior to heart damage, they were able to “mend their heart” as fast as female zebrafish.

Sexual differentiation in zebrafish is more complex than the XY chromosome distinction in mammals. Instead, the combination of many different genes and environmental conditions affect sex. As a result some pollutants called endocrine disruptors can lead to transexuality in marine life. This story may illustrate the physiological function of sexual fluidity.

Story contribution:

Dr Lam Yun Wah
Associate professor
Department of Chemistry
City University of Hong Kong
Tat Chee Road, Kowloon Tong
Hong Kong