Genes from fireflies and jellyfish were recently used in a study Europe that could help identify some of the causes of infertility and autoimmune diseases.

These luminescent and fluorescent qualities that light up the bodies of fireflies and jellyfish produce a hormone linked to many conditions, such as lupus, rheumatoid arthritis, and inflammation of tissues and cells.

Scientists from the Universities of Edinburgh, Manchester and Liverpool used the genes to light up cells containing prolactin, a hormone that is stimulated during breastfeeding and fills the breast with milk in preparation for the next feed, in rats.

High prolactin levels also play a part in erectile dysfunction, mental problems, and overproduction by pituitary tumors can lead to infertility. The levels peak during REM sleep and are also high after exercise, sleep, sex, and some minor surgical procedures. Prolactin has been linked to over 300 functions of the human body.

The study will help other scientists identify what parts of the body are producing prolactin and how the hormone works.