Home > Your genes > What was the Human Genome Project? > What did the Human Genome Project find? > How was it done?
How was it done?
Your gene instructions are grouped into two sets of 23 'volumes', known as chromosomes, each containing millions of DNA letters, or base pairs. To help them read the entire human genome, scientists took each ‘volume’ and compiled an 'index' – a chromosome map. Some of the landmarks on these maps are genes, others are just short sections of non-coding DNA.
Scanning probe image of chromosome 22 alongside a map of the whole chromosome and a highlighted region showing the gene organisation.
How was the DNA sequence read?
To read the order of letters – or base pairs – in the DNA code, scientists must first break up each chromosome into a set of overlapping pieces. They then use machines to read the order of the letters (the DNA sequence) in each piece. With the aid of computers and the chromosome maps, they reconstruct the order of letters in the complete chromosome.
Scientist loading an automated DNA sequencing machine (left) and reading the results (right).
Principal Funder:
Major Sponsors:
