Q.What is meant by Amitosis?

Amitosis is a primitive, direct form of nuclear division in which the nucleus simply elongates and pinches into two, with no spindle apparatus and no distinct chromosome movement.

Mitosis, the usual mode of somatic cell division, is a highly organised process: chromosomes condense and become visible, a spindle apparatus forms, the nuclear envelope breaks down, and sister chromatids are actively pulled apart to opposite poles before two new nuclei re-form. Amitosis (also called direct division) is a much simpler alternative process, first described (though its interpretation has since been revised) as occurring in this stepwise way:

• The nucleus elongates and develops a constriction (a narrowing) roughly across its middle.
• The constriction deepens progressively until the nucleus is pinched apart into two separate daughter nuclei, without the DNA visibly condensing into distinct chromosomes and without any spindle fibres being formed to actively segregate genetic material.
• The cytoplasm then divides (cytokinesis) in a similarly simple/direct manner, giving two daughter cells, each receiving a nucleus. …