If bdelloids are not having sex, how can they avoid the accumulation of deleterious mutations or generate new diversity? The bdelloid genome shows evidence for other ways of maintaining healthy genes and viable lineages. One is gene conversion, in which one allele replaces another through DNA repair mechanisms or other strategies. The other is horizontal gene transfer (HGT), the transfer of DNA from one organism to another, which is common among microbes yet rarely seen in animals. At least 8 percent of the rotifer’s genes, more than in any other animal, are likely to have been acquired by HGT.