Ivory poaching has driven the rapid evolution of tuskless African elephants, according to a new study from a Princeton University-led group appearing in Science this week. The selective killing of species that with anatomical features such as tusks and horns is the basis of a multibillion-dollar illicit wildlife trade, and intensive poaching in Africa has been associated with an increase in the frequency of tuskless elephants, nearly exclusively among females. Survey data analyzed in the study revealed tusk-inheritance patterns consistent with an X chromosome-linked dominant, male-lethal trait. Meanwhile, whole-genome scans implicated two candidate genes with known roles in mammalian tooth development. Notably, one of the genes is associated with an X-linked dominant, male-lethal syndrome in humans that diminishes the growth of maxillary lateral incisors, which are homologous to elephant tusks. The findings, the study's authors write, provide evidence for "rapid, poaching-mediated selection for the loss of a prominent anatomical trait in a keystone species."
Science Paper on How Poaching Drove Evolution in African Elephants
Oct 22, 2021