The offspring are clones of their mother and do not inherit any of the male's DNA. Typically, when creatures reproduce asexually, harmful changes creep into their genes over many generations. The species will eventually have problems reproducing and can often fall victim to extinction. Scientists at Edinburgh University have been studying complex mathematical models on a highly powerful computing system to look at the case of the Amazon Molly. Researchers calculated the time to extinction for the fish based on modelling genetic changes over many thousands of generations.