Centre for Early Life Christmas Lecture - The evolution of embryo selection with Professor David Haig
Organisms that make minimal prezygotic investment in offspring frequently produce more embryos than can be provisioned. The excess embryos are aborted before major commitment of resources. Such a system increases the average fitness of provisioned offspring if embryos of lower expected fitness are selectively culled. A subset of human embryos are similarly aborted in what may be an analogous mechanism of quality control. The earliest stages after conception are expected to be a period in which embryos are required to demonstrate their metabolic efficiency if they are to avoid elimination.