And when nondisjunction actually takes place, in Meiosis One. That can lead to more serious problems than when it takes place in meiosis two. Because in this case, we're producing a cell with two extra chromatids and with two less chromatids. But in this case, we're producing a cell with one extra and one less chromatid. Now, what kind of problems can this cause? Well, whenever a cell is missing a set of genes, a set of DNA, that means it cannot actually synthesize certain types of proteins.