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The Human Genome Project was the largest international collaboration ever undertaken in biological science, bringing together researchers from the US, UK, France, Germany, Japan and China.

The project was launched in 1990 and took 13 years to complete, costing an estimated $2.9 billion. It was entirely publicly funded and saw off stiff competition from the private sector in the race to sequence the human genome.

How was it done?

A human genome was fragmented and cloned into bacterial artificial chromosomes, which were used to create a contiguous map of overlapping fragments. The cloned fragments were then individually sequenced using Sanger sequencing and the entire sequence was then assembled according to the map.

The draft sequence was first published in the journal Nature in 2001. In April 2003, researchers announced that the full reference sequence of more than 3 billion base pairs was complete, with the finished ‘gold standard’ sequence being published in Nature in 2004.

This reference human genome sequence has proved an invaluable, game-changing resource for the worldwide scientific community, transforming biomedical research and ushering in the era of genomic medicine.

As US National Human Genome Research Institute director Francis Collins aptly described it: “It’s a shop manual, with an incredibly detailed blueprint for building every human cell. And it’s a transformative textbook of medicine, with insights that will give healthcare providers immense new powers to treat, prevent and cure disease.”

Missing parts?

Although the full reference sequence announced as complete in 2003 was a major transformative achievement, there have been many updates since then to refine and improve it.

It is only recently that some parts of the genome been sequenced at all – most notably, the centromeres and telomeres. These parts of the genome are difficult to sequence because they are highly repetitive.

Key messages

  • The Human Genome Project was an international collaborative research project undertaken between 1990 and 2003 to map, sequence and freely publish the entire human genome.
  • A major transformative project, the Human Genome Project provided the first gold standard reference sequence as a crucial resource. This has impacted research and healthcare since, ushering in the era of genomic medicine.
  • Although the Human Genome Project announced in 2003 that the full reference sequence was as complete, there are some parts of the genome that have only recently been sequenced.


For clinicians



Tagged: Sequencing, Technologies

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  • Last reviewed: 03/03/2022
  • Next review due: 03/03/2023
  • Authors: Dr Amy Frost
  • Reviewers: Professor Kate Tatton-Brown