Database Reference
In-Depth Information
The Structure of DNA
The discovery in 1953 by Francis Crick and James D. Watson, using experimental data col-
lected by Rosalind Franklin and Maurice Wilkins, that DNA has a double helix structure
was one of the greatest scientific discoveries of the 20th century. Their
Nature
article en-
titled “Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid”
contains one of the most profound and understated sentences in science:
Ithasnotescapedournoticethatthespecificpairingwehavepostulatedimmediatelysuggestsapossible
copying mechanism for the genetic material.
This “specific pairing” referred to the observation that the bases adenine (A) and thymine
(T) always pair together and guanine (G) and cytosine (C) always pair together; see
Fig-
ure 23-2
. This deterministic pairing enables a “copying mechanism”: the DNA double helix
unwinds and complementary base pairs snap into place, creating two exact copies of the
original DNA strand.
