Table 2.

A few characteristic features of established bio-markers

S. No	Parameter	Technique
		DC	MN	FISH	γ-H2AX
1	Culture time (h)	48	72	48	Not applicable
2	Scoring speed (cells/d)	About 150	About 750	About 750	About 100/h
3	Type of aberrations detectable	Unstable	Unstable	Stable/ unstable	Unstable
4	Period of detection after exposure (yr)	2-3	2-3	> 30	2-3 d
5	Cell type/quality	Metaphases/ good	BN cells/good	Metaphases/good	Interphase cells/good
6	Baseline frequency	0.001	0.015	0.001	0.042
7	Sensitivity (Gy)	0.1	0.25	0.1	0.05

FISH: Fluorescence in situ hybridization; MN: Micronucleus; DC: Dicentric chromosome.