The purpose of in vitro testing is to determine whether an environmental factor, substrate, or any product induces damage to genetic material.
One technique entails cytogenetic assays using different animals cells.
The aberrations detected in cells affected by a genotoxic substance are chromosome gaps, chromatid, complex rearrangements, chromosome breaks, fragmentation, translocation, chromatid deletions, and many more.
One such example is testing for the formation of micronuclei.
The micronucleus test is used as a tool for genotoxicity assessment of various chemicals.
Chromosomal aberration test is easy to conduct in order to evaluate genotoxicity.
A micronucleus is the erratic (third) nucleus that is formed during the anaphase of mitosis or meiosis.
Micronuclei (the name means ‘small nucleus’) are cytoplasmic bodies having a portion of acentric chromosome or whole chromosome which was not carried to the opposite poles during the anaphase.
Micronuclei formation results in the daughter cell lacking a part or all of a chromosome.
These fragments of chromosome or whole chromosomes normally develop nuclear membranes and form as micronuclei as a third nucleus.
After cytokinesis, one daughter cell ends up with one nucleus and the other ends up with one large and one small nucleus, i.e., micronuclei.
There is a chance of more than one micronucleus forming when more genetic damage has happened.