Percentage of Allium cells with various chromosomal aberrations after exposure for 48 hr to ZDV or NVP.

aSticky chromosomes refer to the tendency of chromosome arms or entire chromosomes to stick together.bChromatin bridges occur in mitosis when the telomeres of sister chromatids fuse together and fail to completely segregate into their respective daughter cells. cVagrant forms refer to chromosomal formations different from the normal formation during mitosis.dBinucleated cells have more than one nucleus. eMultipolar mitosis occurs when the chromosomal material is pulled to more than two poles, resulting in the formation of a corresponding number of nuclei. fChromosomal fragments refer to fragments of a chromosome that may be lacking a centromere and so is often lost when the cell divide.