Question

When the prophase chromosome are stained with acetocarmine, they take differential staining. This phenomenon is called as

• A. ldiogram
• B. Karyotype
• C. Heteropycnosis
• D. Satellite

Answer 1

The correct option is C Heteropycnosis

Heteropycnosis is a phenomenon shown by chromosomes in which certain regions of chromosomes stain more intensely than others. The regions which exhibit heteropycnosis may be said to be composed of heterochromatin as described by Heitz (1928), and called heterochromatic parts against the other parts, which never show heteropycnosis and called euchromatic parts. In 1928, Heitz defined heterochromatin as those regions of the chromosome that remain condensed during interphase and early prophase and form the so called chromocenters. The rest of the chromosome, which is in a non-condensed state, was called euchromatin. Heterochromatin is closely associated with the nucleolus. So, when the prophase chromosome are stained with acetocarmine they take differential staining due to presence os heterochromatin and euchromatin regions. This phenomenon is called as heteropycnosis.

Idiogram is a written symbol that represents an idea or object directly rather than a particular word or speech sound.

A karyotype is simply a picture of a person's chromosomes.

Satellite DNA is the main component of functional centromeres and form the main structural constituent of heterochromatin.