26 January 2016
Vol 9, Issue 412

About The Cover

Cover image expansion

Online Cover This week features a Research Article that explains how placental development and embryo survival require a minimum amount of the functionally redundant kinases MEK1 and MEK2. The image shows mouse embryos of different genotypes, representing how some embryos die due to placental defects when a single copy of Mek2 is introduced into a Mek1-null background. [Image: Rifdat Aoidi/Centre de recherche sur le cancer de l'Université Laval, Québec, Canada]