Alexander van Oudenaarden is group leader at the Hubrecht Institute and professor of quantitative biology of gene regulation at the University Medical Center Utrecht and Utrecht University. The Van Oudenaarden group combines biology with physics and informatics to gain insight in the quantitative biology of development and stem cells. They develop new techniques to quantify gene expression and study the regulation of gene expression in single cells. Alexander van Oudenaarden is one of the pioneers of single cell RNA-sequencing and his lab has developed several bio-informatics tools to analyze these data in detail. Their main interest is to investigate the mechanisms by which cells with the same genotype and identical growth environment develop different phenotypes.