May 17, 2006

Chromosome 1

Chromosome 1 analysis completes the Human Genome Project's chromosome-paper series

The last chromosome paper was also the largest: 223,569,564 DNA letters — enough, by one estimate, to fill roughly 60,000 typed pages.

17 May 2006: the biggest chromosome, last in line

On 17 May 2006, the Wellcome Trust Sanger Institute announced publication in Nature of the sequence and analysis of human chromosome 1 — the largest human chromosome, and the last to receive its dedicated analysis in the Human Genome Project's peer-reviewed series. (The Sanger announcement is dated the 17th; Nature's formal issue date is 18 May.)

The finished sequence ran to 223,569,564 bases — about 8 percent of the genome — at greater than 99.99 percent accuracy, covering 99.4 percent of the chromosome's amenable euchromatic sequence. The work was done principally at Sanger, with the University of Washington Genome Center contributing 13 percent of the finishing.

What 'final chromosome' actually means

The framing needs care: the Human Genome Project had ended in 2003, and its chromosome sequence data had already been released. This paper completed the series of peer-reviewed analyses covering the 22 autosomes plus X and Y — it did not newly create a gapless genome.

'Finished,' 2006-style, still left about 1.3 million base pairs of gaps inside the assembly, and the centromere and heterochromatic repeats — part of an estimated 237.6-million-base total — remained outside it.

What the sequence held

The annotated chromosome became a public resource for studying sequence variation, disease-related genes, recombination, replication and chromosome biology. The analysis identified almost 4,500 single-letter variants that could alter proteins, 90 of them predicted to shorten one.

In conventional chromosome-by-chromosome ordering, the human genome's first base is C — not G.

Sources

Researched 23 Aug 2026 7 sources 3 audit passes, 1 issue open Date disputed

How this was checked

Researched from the web into a fact sheet, rewritten from that sheet, then audited against it by a different model. How the pipeline works →

Date disputed. Sources disagree about when this happened.

What the sources leave uncertain

The Sanger Institute announcement is dated May 17, 2006 and says the paper was published that day. PubMed and Nature cite the journal issue as May 18, 2006. May 17 is defensible as the announcement/release date; May 18 is the formal issue date.
Calling this the date the Human Genome Project 'published the final chromosome sequence' can mislead: the HGP had ended in 2003, and chromosome sequence data had already been released. This was the last dedicated chromosome analysis in its peer-reviewed paper series.