And this process is known as disjunction. Now, just like any other biological process, disjunction is also prone to mistakes. And one mistake that can take place during this junction is an unequal or an incorrect separation of chromosomes. And this is known as nondisjunction. So non disjunction is the process by which the chromosomes actually fail to separate correctly or equally during anaphase of either mitosis or mitosis. And this results in cells that have an incorrect number of chromosomes.