Double helix images

A series of images representing double helix images.

• DNA double helix and sequencing output: molecular model of a DNA double helix showing the individual atoms (apart from hydrogen) as coloured balls. Carbon atoms are in white, oxygen in red, phosporus in purple and nitrogen in blue. The background shows the fluorescent banding of the sequencing output from an automated DNA sequencing machine. 

Credit: Peter Artymiuk, Wellcome Images

• Human chromosomes in metaphase: Scanning probe/Atomic Force Microscope image of human chromosomes in a metaphase spread.

Credit: Dr T J McMaster, Wellcome Images 

• Pencil sketch of the DNA double helix: it shows a right-handed helix and the nucleotides of the two anti-parallel strands.

Credit: Francis Crick, Wellcome Library, London

• Separation of DNA fragments by electrophoresis: separation of DNA fragments by electrophoresis through an agarose gel. An electric current is passed through the gel and separates the DNA fragments according to size. The mixture of fragments is applied to a well at the top of the gel before the current is started. The smaller fragments travel further and reach the bottom of the gel while the larger ones remain towards the origin.

Credit: Guy Tear, Wellcome Images

This resource is part of the Post 16 genetics and genomics collection of resources.