Study shows that a single genetic change could have made the ape lineage tailless for 25 million years. Neither chimpanzees, nor orangutans, nor monogamous gibbons have tails.
A short jumping gene —a fragment of DNA known as an Alu sequence —landed in a non-coding part of a gene. This proximity to another Alu element changed the activity of the TBXT gene, which began to produce a different protein than the one that usually makes the tail grow.