by the year 2000. The Sanger centre is expected to produce 33% of the working draft and the three major American genome sequencing centres (Washington University School of Medicine at St. Lois, Baylor College of Medicine and the Whitehead Institute of Technology) are expected to achieve 60% between them. Other centers notably in France, Germany and Japan, are also commited to sequencing specific subchromosomal regions (electronic ref 4). After completion of the working draft, the full genome sequence is expected to be achieved around 2002-2003.OddHuman genetic maps based on microsatallite markers, although extremely valuable, have some limitations. In particular, although such markers are found all over the genome their density is limited to about one per 30 kb. In addition, typing of microsatallite markers is not so amendable to automation on a very large scale. By contrast, single nucleotide polymorphisms (SNPs) are very frequent (about 1 per kb) and typing is easily automated because they have only two alleles. (section 11.2.3). As a result, they have been envisaged to have potentially powerful applications in association studies to identify genes underlying polygenic disease (Collins et al., 1997; Schafer and Hawkins, 1998). The first steps towards establishing a third-generation SNP-based genetic map have recently been described by Wang et al.,(1998). Partly in response to initiatives from the private sector (see box 13.2), the US Human Genome Project and the UK welcome trust have committed funds for the construction of a map containing 100 000 SNPs by 2003. However, the utility of SNPs remains unproven and some emerged data has dampened the initial optimism (Pennisi, 1998).Mapping the human genome is not the only scientific focus of the human genome project; at it’s outset, the value of sequencing genomes of model organisms was recognised. Such organisms include a variety of species, some of which have been particularly amen...
