[In Depth] Fossil fishes challenge ‘urban legend’ of evolution
The diverse group of fishes called teleosts, or ray-finned fish, today has 30,000 species, more than all living mammals, birds, reptiles, and amphibians combined. For more than a decade, many researchers have assumed that teleosts' dizzying array of body types evolved because their immediate ancestor somehow duplicated its entire genome, leaving whole sets of genes free to take on other functions. Now, an examination of the fish fossil record challenges that view. Despite a genome duplication about 160 million years ago, teleost fish hewed to a few conventional body types for their first 150 million years. Meanwhile the holostean fishes, a related group with genomes that never underwent a doubling, evolved a stunning diversity of body plans. This work and studies of flowering plants, which are also quite diverse, is forcing a rethink about just how genome duplications influence evolution. Author: Elizabeth Pennisi