🇺🇸
/əˈmɪtoʊsɪs/
🇺🇸
/əˈmɪtoʊsɪs/
🇬🇧
/əˈmɪtəsɪs/
🇬🇧
/əˈmɪtəsɪs/
Plural
amitoses
Amitosis is a simple, direct form of nuclear division where the nucleus splits without chromosome condensation, spindle formation, or typical mitotic stages — common in some protozoa, aging cells, or pathological conditions. Unlike mitosis, it's often unequal and doesn't ensure identical genetic distribution, making it more like 'splitting without ceremony'.
In certain ciliates like Paramecium, amitosis occurs alongside conjugation to maintain nuclear dimorphism.
Pathologists sometimes observe amitosis in highly abnormal tumor cells that have lost regulatory control over division.
Unlike healthy human somatic cells, which divide by mitosis, some senescent cells may resort to amitosis as a last-resort replication mechanism.
Amitosis lacks the precise chromosome segregation seen in mitosis, leading to genetic heterogeneity among daughter nuclei.
Early microbiologists mistakenly classified bacterial binary fission as amitosis before understanding its molecular distinction from eukaryotic amitosis.
a-
Comes from the Greek prefix 'a-' (alpha privative), meaning 'without' or 'not'. It negates the meaning of the root it attaches to. Examples include amoral, atypical, asymmetrical, asexual.
mitos
Comes from the Greek noun 'mitos' (μῖτος), meaning 'thread'. In biology, it refers to chromatin threads (chromosomes) visible during cell division. This root is central to terms like mitosis, meiosis, and mitochondrion (originally 'thread granule').