The goal of the lab is to decipher molecular mechanisms that help cells “do maths” during development – after all, cells are able to interpret numerical information, like the number of chromosomes in their nucleus or the gradients of morphogens in the extracellular space, and then “make” decisions based on that, such as which cell types to become. In particular, the lab focuses on how cells sense and interpret differential gene dosage, i.e., the number of copies of a gene in the genome. This includes studying the mammalian X chromosome, which is most often present in either one or two copies in the nucleus, in XY or XX cells, respectively. This difference has had important implications during the evolution of mammals, including the emergence of a dosage compensation mechanism – X-chromosome inactivation – in XX individuals. As model systems, the lab uses mouse embryonic stem cells and mouse embryos, following the ethical considerations associated with them, as well as human cell lines.