Genomes, genomes everywhere - but where to browse?

Genomes, genomes everywhere – but where to browse? The first full unicellular organism to be sequenced was Saccharomyces cerevisae in 1996 1 and two years later the first multicellular eukaryotic genome was that of Caenorhabditis elegans. 2 Subsequently there has been an explosion in the number of genome projects. Potentially the most useful in medical terms, the Human Genome Project, carried out in 16 centres across the world, announced completion of the working draft sequence in 2001. 3,4 Over 85 per cent of the human genome had been accurately deciphered and a total of 97 per cent of it had been sequenced at least five times. The finished sequence was announced in 2003 with a highly accurate, highly contiguous sequence displaying fewer than one error per 10,000 bases. Only gaps corresponding to regions whose sequence cannot be reliably resolved with current technology remain. The full length human genomic sequence (known as a build) is created automatically using curated Tiling Path Files indicating clone order and overlap with the location of gaps for each individual chromosome. These are provided by the Human Sequencing Consortium and are used together with high-throughput genomic (HTG) sequence reads to complete a map of the entire genome as an ordered set of contigs (known as a scaffold) to include the location of all bases in the correct order across the genome. To populate the browsers with the same scaffold data and provide a frame of reference for researchers, each genome project is frozen at a particular stage in finishing the sequence. This freeze is the build that is used as the framework onto which each browser hangs the annotation. Other genomes are built using a similar method. This is an automated process, and involves the construction of a region spanning billions of bases. Errors during this process result in the absence of a specific region of the genome. This happens to well-known regions as well as novel regions and will be fixed if the relevant consortium is alerted. As the build is currently dynamic, the remaining gaps are constantly being filled and chromosomal coordinates may change with each assembly. The wealth of data that has accumulated as a result of this myriad of genome sequencing projects around the world has opened the door on further understanding of the mechanisms by which biological functions are achieved. This global genome project is so large, however, that making the …