Micronuclei waa koromosoomyada oo dhan ama jajabyo acentric ah ama koromosoomyada giraanta kuwaas oo ku sii jira cytoplasm marka koromosoomyadu ay si joogto ah u galaan unugyada gabadha si ay u sameeyaan nuklei ka dib mitosis.
Horumarinta shirkaddaada, waxay noqdaan kuwa waaweyn ee dhinacyada la xidhiidha Shiinaha. Xitaa haddii ay iibsadaan in ka badan 20 baabuur oo alaab gaar ah oo ay sameeyaan, si fudud ayay u samayn karaan. Haddii ay tahay wax iibsi badan oo aad raadinayso, way ku dabooleen.