Sperm gene BOULE shared by organisms regardless of species. A study conducted by geneticist Eugene Xu from Northwestern University was published in the July 15, 2010 PLoS Genetics journal. Xu found that sperm contain the gene BOULE, the only gene identified to exist only for sperm production. Xu and his team studied sperm from sea anenome, sea urchins, fruit flies, rainbow trout, a rooster, and a mouse. Xu concluded that BOULE is ancient in origin. Xu's study and resulting conclusions suggest that sperm production has been conserved throughout animal evolution for over 600 million years. Xu stated in the journal: "People have thought there was no single common ancestor because we see sperm reproduction in many animals, but previously there was no conclusive evidence ethat sperm production has a single common origin in all animals."
Scientists and researchers are hopeful that by identifying BOULE they will be able to develop a male contraceptive based upon targeting BOULE and blocking the gene. Xu believes that blocking the gene will not interfere with other bodily operations, unlike other genes previously identified in sperm production. Xu stated in PLoS Genetics: "We'd found genes before that were involved in sperm production but also in other functions in the body like hormonal regulation."