amitotic

Amitotic refers to a form of nuclear division that occurs without the characteristic mitotic processes such as the formation of a spindle apparatus, chromosomal condensation, and the breakdown of the nuclear envelope seen in mitosis. The term amitosis is historical and is often used to describe such divisions in some organisms or experimental contexts, but it is not generally used to describe standard cell division in most metazoans.

Mechanistically, amitosis involves a simple division of the nucleus, sometimes by constriction or by an uneven distribution of chromatin, without a visible mitotic spindle. The cytoplasm may divide afterward, but the process does not proceed through the conventional stages of mitosis. As a result, daughter nuclei can inherit chromosomes in an imperfect or unequal manner, leading to genetic variability or instability.

Amitosis has been reported in certain unicellular eukaryotes and in some experimental cell systems. In many cases described as amitosis, subsequent studies have shown that the division is better explained by atypical or incomplete mitosis, and the term is increasingly viewed as outdated. In more complex tissues and organisms, true amitosis is considered rare, with most cell divisions proceeding via canonical mitotic mechanisms or through other well-defined modes of division.

Overall, amitosis remains a historical concept used to describe non-standard nuclear division, but contemporary cell biology typically interprets such observations within the framework of mitosis or recognizes them as artifacts or atypical variants of mitotic processes.