Question

Barr body in mammals represents

• A. all the heterochromatin in male and female cells
• B. the Y-chromosome in somatic cells of male i
• C. all the heterochromatin in female cells
• D. one of the two X-chromosomes in somatic cells of females. \

Answer 1

Answer: (D)

one of the two X-chromosomes in somatic cells of females. \

Answer 2

Barr body is a condensed heterochromatic copy of the X chromosome, visible by staining the interphase nucleus of somatic cells of the homogametic sex, for example the human female. Named after M. Barr, these condensed chromosomes offer an easy way of determining the true genetic sex of individuals with intermediate secondary sexual characteristics. The total number of Barr bodies is always one less than the total number of X chromosomes present in the cell or the organism.