The yeast genome is sequenced

In 1996 an international consortium announced the complete genome sequence of Saccharomyces cerevisiae. Baker's yeast became the first eukaryote whose genome was known in full. The project required collaboration between laboratories in many countries, the harmonisation of data, and the assembly of the sequences of sixteen chromosomes at a time when today's rapid technologies did not exist.

The genome has about twelve million base pairs, and more than six thousand protein-coding genes were originally predicted in it. Later curation refined gene boundaries and removed some incorrect predictions, which is a normal stage in work with a reference genome. The most important result was not one final figure but a complete map allowing gene functions to be studied systematically.

Saccharomyces cerevisiae is easy to culture, grows quickly and can exist as a haploid or a diploid cell. Researchers can alter its genes precisely, and many basic cellular processes — the cell cycle, transport within the cell, DNA repair — have counterparts in humans. The full sequence made it possible to create collections of mutants and to study gene networks at the scale of a whole organism.

The significance of the project extends beyond yeast and fermentation. It showed that a large consortium can assemble the genome of a nucleated organism and make publicly available a resource useful for thousands of experiments. The consortium's review article in Nature documents that historic moment. Today's sequencing is faster, but the main principle has remained: a reference genome is the beginning of interpretation, not a complete instruction for life recorded without uncertainty.

Completion in 1996, directory in 1997

NHGRI’s release of 24 April 1996 records the actual completion milestone: an international consortium determined the order of 12,057,500 bases in the nuclear DNA of Saccharomyces cerevisiae. The result comprised about 6,000 genes on 16 chromosomes; chromosome III had already been completed in 1992, the first eukaryotic chromosome to be fully sequenced. The project was decentralised: NHGRI names 92 European Union laboratories plus teams in the United States, Canada, the United Kingdom, and Japan. A year later, Nature described more than 600 scientists at over 100 laboratories and called the resource the first complete set of genes from a eukaryotic organism. A complete, ordered sequence made it possible to investigate gene function across an entire cell rather than one locus at a time.