Contact: Natalie Bouaravong
Public Library of Science
Caption: The emergence of alternative nourishment resources (lactation and placentation) during mammalian evolution set the stage for mammals' progressive loss of egg yolk nourishment (as a consequence of the loss of egg yolk genes).
Credit: Image: Rasmus Kaessmann
Usage Restrictions: Attribution must be given to the photographer, Rasmus Kaessmann.
Related news release: Loss of egg yolk genes in mammals and the origin of lactation and placentation