African clawed frog genome contains two full sets of chromosomes from 2 two extinct ancestors

Millions of years ago, one species of frog diverged into two species. Millions of years later, the two frogs became one again, but with a few extra chromosomes due to whole genome duplication. Such is the curious case of the African clawed frog, a frog whose genome contains nearly double the number of chromosomes as the related Western clawed frog.
Strange & Offbeat: Fossils & Ruins News — ScienceDaily