Box 1.2Units of length for DNA molecules

Because DNA is double-stranded, the lengths of molecules are described as so many base pairs (bp). A kilobase pair (kb) is 103 bp and a megabase pair (Mb) is 106 bp. A gigabase pair (Gb) is 109 Mb. In summary:

1 kb = 1000 bp

1 Mb = 1000 kb = 1 000 000 bp

1 Gb = 1000 Mb = 1 000 000 kb = 1 000 000 000 bp

Lengths of RNA molecules cannot be expressed in bp because most RNAs are single-stranded: their lengths must therefore be described as so many nucleotides.

From: Chapter 1, The Human Genome

Cover of Genomes
Genomes. 2nd edition.
Brown TA.
Oxford: Wiley-Liss; 2002.
Copyright © 2002, Garland Science.

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