Questions & Answers

The Barr body is observed in
A. Basophils of male
B. Neutrophils of female
C. Neutrophils of male
D. None of the above

Answer Verified Verified
Hint: A Barr body is the inactive X chromosome during a female vegetative cell, rendered inactive during a process called as lyonization, in some species during which sex is decided by the presence of the Y or W chromosome instead of the diploidy of the X or Z.

Complete answer: In cells with multiple X chromosomes, about one of them is inactivated during mammalian embryogenesis. This takes place early on during the onset of embryonic development randomly in mammals (except in marsupials) and in some extra-embryonic tissues of some placental mammals, during which the X chromosome from the sperm is usually deactivated.
In humans possessing only one X chromosome, the amount of Barr bodies visible at the interphase stage of cell division is usually one fewer than the net amount of X chromosomes.
Barr bodies are often seen within the nucleus of neutrophil cells in the blood, usually at the rim of the nucleus in female autosomal cells in between cellular divisions.

So, the correct answer is option B. Neutrophils of females.

Note: Recognition of a Barr body present in a neutrophil is vital so as to avoid any kind of abnormality (unless two or more Barr bodies are seen per neutrophil). The Barr body is taken into account nonpathological unless related to rare chromosome disorders.