Each of these boxes holds the early signs of new human life. The video shows blastomeres – the cells formed from a fertilized egg – dividing at first into two cells, then two into four. Cell division at this delicate stage must be precise: the DNA received just hours ago from mother and father must be split equally between dividing cells. Unequal division, known as aneuploidy, can lead to birth defects or diseases in later life. DNA inside some of these blastomeres is breaking off into unequal fragments (see the troubled blastomere in the centre of the bottom row). The overlaid coloured spots show a computer program scanning the blastomeres for such fragments – effectively screening for ‘faulty’ embryos. Knowing which embryos are likely to develop healthily prior to injection into the uterus could increase the success of future IVF treatments and decrease the risk of miscarriage during pregnancy.
Written by John Ankers
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.