Grant: Project Grant

Many patients wishing to conceive will be referred to Assisted Reproduction Clinics, where embryos are created by In Vitro Fertilisation (IVF) prior to transferring them to the patient to establish a pregnancy. In these procedures a key decision that is made is which embryo to transfer to the patient. However, current selection methods remain ineffective. Better methods for selecting the best embryo require a more detailed understanding of the biology of the early embryo that we currently have. Here we are focusing on a phenomenon termed 'mosaic aneuploidy' wherein it is well known that cells within the early embryo frequently contain the wrong number of chromosomes. This notion is central to many embryo selection approaches, but the underlying reason for the aneuploidy and its impact upon the embryo remains extremely poorly understood, and a better understanding would help development of better selection methods. Here, using mouse embryos and human embryos donated to research, we seek to understand why these aneuploid cells are far more common in the early embryo than in other normal tissues. We hypothesise that this is because mechanisms that would normally detect aneuploid cells and then eliminate them are turned off in the early embryo. We will directly test this hypothesis, and study the molecular details as to why this is the case. Our experiments will shed much needed light on the biological meaning of embryo mosaicism, and provide insight that will be useful in the further development of embryo selection protocols.