Question

The Klinefelter syndrome is a genetic disease caused by an extra copy of the X sex chromosome in males. Patients have 47 chromosomes (also written as 47, XXY to denote that the patient has an extra X. Describe the two genetic scenarios leading to patients with Klinefelter syndrome. Drawings encouraged.

Answer 1

Mother with dysjucntion at meisosi 1 and father with dysjunction in meiosis 1

the mother having two x chromosoe when undergo meiosis allow the sepration of homologous pair of x chromosome whenthesechromosomes donot apart in meiosis 1 lead to formation of two x chromosome in a single cell and other cell having no x chromosome.

similarly male having one x chromosome when chromosome sepratae allow two gamete with if these homologous of x donot separate during meiosis 1 in male lead to two x chromosome in single gamete. when fuse with normal femle gamete produce xxy genotype

this proces of non separation.during meiosis 1or 2 is called dysjunction defect.