Resources by Wellcome Images

Electrophoresis gel with annotation

Di-deoxy sequencing is a way to determine the order of bases (A,C,G and T) in a piece of DNA. A set of 4 lanes (one for each base) is needed to sequence any given piece of DNA. Wherever a black
band appears in a particular lane that base is present. By reading off the order of bands across the four lanes the...

Automated DNA sequencing output

The output from an automated DNA sequencing robot used by the Human Genome Project to determine the complete human DNA sequence. Each peak shows the presence of a particular base. The sequence of bases in a given stretch of DNA can therefore be read from the order of the peaks along the trace. The sequences of...

Chromosomes in metaphase

An image representing human chromosomes in metaphase. Atomic Force Microscope image of ...

Di-deoxy sequencing gel with annotation

Di-deoxy sequencing is a way to determine the order of bases (A,C,G and T) in a piece of DNA.  A set of 4 lanes (one for each base) is needed to sequence any given piece of DNA. Wherever a black band appears in a particular lane...

DNA replication theory

Diagramatic representation of the replication of DNA. This is the process by which the cell makes a copy of its existing DNA before it divides. This therefore ensures that each new cell receives a full complement of DNA. The DNA polymerase enzyme can only add new bases in the 5'-3' direction. This leads to...

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....

Hydrogen bonding

Diagram showing the hydrogen bonds that form between the four bases in the DNA double helix. These weak forces between the bases keep the two complementary strands of DNA together and ensure that the correct bases are put in the right place during replication of the DNA molecule. A always pairs with T and C always...

Semi-conservative replication images

A collection of images representing semi conservative DNA replication:

Illustration depicting semi-conservative DNA replication 1. Three generations of DNA are shown. After separation of the DNA double helix, two new complementary DNA strands are synthesised (indicated by a new colour)....