Index >> Sex Chromosomal Non-Disjunctions

Sex Chromosomal Non-Disjunctions
During normal cell division, each daughter cell receives an exact complement of autosomes and sex chromosomes, either a copy of each chromosome (in mitosis) or one each pair of chromosomes (in meiosis). But under certain circumstances (such as abnormal functioning of spindle apparatus) one or more chromosomes may fail to migrate properly towards opposite poles during anaphase. Thus, two homologous autosomes or sex chromosomes, which should part and go one into each daughter cells, remain, stick together and result in two types of daughter cells, i.e., one which receive both homologous partners and another which fail to receive anyone of them. The phenomenon in which two homologous chromosomes fail to separate or disjoin with each other during anaphase of either mitotic or meiotic cell division is called non-disjunction.