Transmissible cancers arise rarely in nature. However, these contagious clones may be more frequent than is known at present. We tested whether two cancers affecting aquatic animals are clonally transmitted. Fibropapillomatosis is a cancer affecting green sea turtles, and goldfish are frequently affected by a type of schwannoma. We used a genetic approach to test the hypothesis that these cancers are clonally transmitted. The results suggested that this is not the case. Read the full story here, published in Wellcome Open Research!