University of Adelaide researchers have found the first tangible evidence. The ancestors of some of Australia’s most venomous snakes arrived by sea and not by land. It is the dispersal route of most other Australian reptiles.
The study has been published in Genes. Scientists analyzed the genomes of two Australian elapids. These are tiger and a brown snake. They compared them to marine and semi-marine elapid sea snakes and Asian elapids.
Scientists inferred that the ancestor of all Australian elapids had accumulated self-replicating and self-mobilizing genes. These are not present in their land relatives. These came from another source altogether.
Scientists identified 14 distinct transfer events of the new genetic material from other marine organisms. There were eight genes uniquely present in the marine and semi-marine sea snake genomes. In the semi-marine snake genome, the acquired genes were as much as 8–12 percent of the total genome sequence.
This means scientists can unambiguously determine the major genetic differences between land and marine snakes. They were a consequence of migration into a marine environment. For the first time the jumping genes have been used to confirm the evolutionary history of any animal species. This research has proved that the common ancestor of all Australian elapids adapted to a marine environment.