Medical Research Council - London Institute of Medical Sciences

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Four novel DNA 'building blocks' added to A, T, C, G bring the potential for 'alternative' synthetic DNAs with novel applications

06 April 2019

DNA Doubled

Naturally occurring DNA consists of four building blocks, or nucleotides, spelled out by the letters G, C, A and T. Scientists have calculated that, in theory, other 'letters' chemically similar to the existing four are capable of integrating into DNA molecules. But, for whatever reason, evolution did not choose them. Putting that theory to the test, researchers have now shown that indeed four of these alternative nucleotides (Z, P, S and B) can, together with G, C, A and T, form DNA molecules with double the genetic alphabet. This synthetic DNA looks and behaves like the real thing. The video shows a molecular model of the eight-letter DNA with a standard double-helix structure – and can even be used to make eight-letter RNAs – DNA-encoded molecules with catalytic capabilities. By creating RNAs with novel nucleotides, the potential functions of these molecules have vastly increased, as have their potential biotechnological and medical applications.

Written by Ruth Williams

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