This is an open access article distributed under the terms of the Creative Commons
Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.EAR is a Herchel Smith Fellow. MB and HB are supported by the Centre for
Trophoblast Research, MB is a Next Generation Research Fellow. MJB is
supported by a BBSRC studentship. The WR lab is supported by BBSRC, MRC,
the Wellcome Trust, EU EpiGeneSys and BLUEPRINT. The SB lab is supported
by core funding from Cancer Research UK