Cloning cattle is an agriculturally important technology. Dot and Ditto were born in the fourth and fifth cow clones born at UC Davis. (Credit: Alison Van Eenennaam, UC Davis Department of Animal Science)
The underlying cause of male infertility is unknown for 30 percent of cases. In a pair of new studies, researchers have determined that the reproductive homeobox (RHOX) family of transcription factors -- regulatory proteins that activate some genes and inactivate others -- drive the development of stem cells in the testes in mice. The investigators also linked RHOX gene mutations to male infertility in humans.