mikronukleusta

Mikronukleusta refers to small, extra nuclei that can be found in cells. These micronuclei are formed during cell division when chromosomes, or fragments of chromosomes, are not properly segregated into the daughter cells. Instead, they lag behind and are enclosed within a separate membrane, forming a micronucleus. This process is often a consequence of DNA damage, chromosomal instability, or defects in the cell division machinery.

The presence of micronuclei is generally considered a sign of genotoxicity, meaning that the cell has been exposed to agents that can damage its DNA. These agents can include certain chemicals, radiation, or even spontaneous errors during DNA replication. Cytogeneticists and toxicologists use micronucleus tests as a biomarker to assess the potential for a substance to cause genetic mutations or chromosomal abnormalities.

Micronuclei can contain whole chromosomes or just chromosome fragments. The genetic material within a micronucleus is not actively participating in the cell's normal functions and can contribute to further genomic instability. Observing and quantifying micronuclei in cells, often through microscopy, is a common method in research to evaluate the mutagenic or clastogenic (chromosome-breaking) potential of various substances and to study the mechanisms of DNA repair and cell cycle regulation.