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Introducing the bacteria

Only one per cent of the world's bacteria -- those that can be cultured in the lab -- are known, but molecular techniques pioneered by the Agricultural and Food Research Council (AFRC) in Britain will enable researchers to identify and classify bacteria into reliable genetic groupings. This will provide a way to rapidly assess newly discovered bacterial species.

Hitherto, bacteria identification has been mainly based on behavioural characteristics, but this has proved an unreliable guide to genetic makeup. The new technique, called the polymerase chain reaction (PCR) technique, is based on mapping the molecules in the ribonucleic acid of the ribosomes, which are the sites of protein synthesis in bacteria. These molecules, known as RNA, can be regarded as chronometers that record the ancestral interrelatedness of bacteria because their nucleic acid sequences contain regions that change at different rates during evolution.

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