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DNA autoradiogram being picked up with a pair of tweezers from a petri dish. An autoradiogram is produced during DNA (deoxyribonucleic acid) analysis. The bands (black) of the autoradiogram correspond to the four nucleotide bases which make up a genetic sequence. Every individual, with the exception of identical twins, has a different genetic sequence. DNA analysis is used in forensic science, medicine and paternity studies. (KEYSTONE/SCIENCE PHOTO LIBRARY/Andrew Brookes) === ===