FISH in analysis of gamma ray-induced micronuclei formation in barley
The distribution of two break chromosome exchanges (dicentrics and centric rings) following gamma or neutron irradiation of resting seeds of rye, Secale cereale, has been investigated. The localisation of heterochromatin in the terminal ends of the chromosomes of rye facilitates distinguishing aberrations involving heterochromatin from others. Dicentrics found in or near heterochromatic regions were about 5 times more frequent after gamma irradiation and about 2.5 times more after neutron irradiation, than expected on a random distribution. The implications of these findings in relation to aberration formation are discussed.