11 High - Throughput Techniques - Genotyping and Genomics Alison

The new field of genomics has emerged from conventional human genetics and is, at present, moving extremely rapidly. As a result, this chapter will be a snapshot in time, capturing a moment in the state of development. For this reason it will not dwell in detail on individual technologies or machines, as many of these will be obsolete in a very short time, but rather on the principles of high-throughput working, which should remain valid for longer. Technologies for high-throughput genotyping have existed for some years and there have been many studies on individual genes or specific loci. It has been possible to add the '-omics' suffix, since the completion of the sequencing of the human genome. We now have the ability to consider the genome as a unified whole rather than as many tiny, and largely unconnected, parts of chromosomes. The first genome-wide scans, using single nucleotide polymorphisms (SNPs) to find multiple genes contributing to single common human diseases are, in early 2007, on the verge of reporting their findings. The first has potentially found four loci for type 2 diabetes (Sladek et al. 2007). Now they have been clearly demonstrated to work, the same techniques will no doubt be applied to many other common diseases and complex genetic traits within a very short time. The tools required for genome-wide studies; bioinformatics resources, high-throughput technologies and a detailed knowledge ofpopulation genetics and evolution, come from previously unrelated scientific fields and yet are all moving forward together and stimulating each other. Effective scientists will need an understanding of all three tools to make proper use of any one. The combined use of them to best effect is still under debate and will only be refined once the outcomes of the first scans have been considered.