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Forensic blood sampling. Forensic scientist's gloved hands cutting a blood-stained piece of a shirt for testing during criminal investigations. DNA (deoxyribonucleic acid) may be isolated from the sample and sequenced, providing a DNA fingerprint. This may then be compared with DNA from the victim and any suspects. In some cases, this may be used in conjunction with other evidence to positively link a suspect with both the victim and the scene of a crime. Modern amplification techniques allow DNA sequences to be taken from extremely small samples, such as a few spots of blood or a few hair follicles. (KEYSTONE/SCIENCE PHOTO LIBRARY/CHR 366 PETER MENZEL/SCIENCE PHOTO LIBRARY) === ===