= Base pair
{title2=bp}
{wiki}
A <base pair> is an association of two <nucleobases> through <hydrogen bonds> in a compatible arrangement. It commonly joins opposite strands of a <nucleic acid double helix>, but can also join two regions of one folded <RNA> strand. Canonical Watson–Crick <DNA> <base pairs> match <adenine> with <thymine> and <guanine> with <cytosine>; canonical <RNA> <base pairs> use <adenine> with <uracil> instead. The <nucleobases> belong to complete <nucleotides>, including their attached <sugars> and backbone <phosphate>. See https://www.genome.gov/genetics-glossary/Base-Pair[NHGRI: base pair].
The abbreviation bp also measures the length of a paired region. Our ACGTAC/TGCATG duplex has six <base pairs>, containing twelve <nucleotides> altogether. Its upper strand contains two <adenine>, two <cytosine>, one <guanine>, and one <thymine> <nucleobase>; the lower contains one, one, two, and two respectively. Combined, the counts are three of each <nucleobase>. Equality of total <adenine> and <thymine>, or of total <guanine> and <cytosine>, need not hold within either individual strand.
Back to article page
