Caption

Cloning genetic fragments. Technician's gloved hands hold an assay tray with fragments of genetic material in front of a monitor displaying results from Polymerase Chain Reaction (PCR) equipment. PCR produces identical copies (clones) of fragments of genetic material, such as RNA (ribonucleic acid) and DNA (deoxyribonucleic acid). The polymerase enzymes used make single strands of genetic material synthesize mirror copies of themselves. Repeating this process produces large numbers of duplicate fragments for analysis. PCR is useful when only a tiny amount of genetic material can be isolated. Photographed at Pharmagene, Royston, Hertfordshire, England.