Sequence analyses of duplicated yolk genes of bony fishes yield new insights for their successful radiation in the oceans during the early Paleocene period. Scientists at the University of Bergen, Norway have deduced how bony fishes conquered the oceans by duplicating their yolk-producing genes and filling their eggs with the water of life – the degradation of yolk proteins from one of the duplicated genes causes the eggs to fill with vital water and float. This is the major solution realized by extant marine teleosts that showed an unprecedented radiation during the late Cretaceous and early Paleocene Periods. The work is a unique hypothesis that integrates the cellular and molecular physiology of teleost reproduction with their evolutionary and environmental history. "The oceans have not always been filled with fishes as nowadays" says researcher Dr. Roderick Nigel Finn at the Department of Biology, University of Bergen, Norway. "To the contrary", Dr Finn says, "the fossil record shows that the ancestors of the bony fishes (teleosts) inhabited fresh water environments for at least 150 million years before they entered the oceans". Click here to read more.