The Biomedical Sciences in Society by Iain Crinson

Author:Iain Crinson
Language: eng
Format: epub
ISBN: 9789811595233
Publisher: Springer Singapore

An Era of Personal Genomics?

Post-HGP, the possibility of using associations found to exist between genetic variants and disease risk to build individual ‘genome profiles’ slowly began to be realised. For nearly two decades both industry and academic genomic scientists have working together in order to establish publically available reference databases on the 4–5 million single nucleotide polymorphisms (SNP). SNPs are the most common type of genetic variation and occur normally throughout a person’s DNA. These variations may be unique or occur in many individuals, and it is on that understanding that more than 100 million SNPs have been found in populations around the world. Most commonly, ‘these variations are found in the DNA between genes. They can act as biological markers, helping scientists locate genes that are associated with disease. When SNPs occur within a gene or in a regulatory region near a gene, they may play a more direct role in disease by affecting the gene’s function’ (National Institutes of Health—‘What are SNP’s).

As it gradually began to be recognised that significant genotype variation occurred across populations, so that the establishment of global SNP databases was seen to be a necessary step in order to gain a purchase on individual variability and predisposition to disease. Once the databases began to be built, they opened up the possibilities for genome-wide association studies (GWAS). GWAS are in principle hypothesis-free methods that seek to examine SNPs across the genome in the study of common but complex diseases, where many genetic variations can contribute to individual’s risk of that disease. As of January 2020, the online database, ‘GWAS Central’, identifies 70,566,447 associations between 3,251,694 unique SNPs and 1451 disease/phenotype descriptions (www.​gwascentral.​org), while the European Bioinformatics Institute GWAS catalogue contains 4628 separate studies (EBI: accessed June 2020). This is a remarkable achievement, given that it was only as far back as 2003 that the US National Human Genome Research Institute (NHGRI) first published its vision for the application of GWAS to develop an individualised preventative medicine initiative.

It was also around this period that the first references to a ‘personal genomics’ were being made, reflecting a move away from the original ‘one-genome-fits-all’ assumption of the HGP, in which the DNA from just a few individuals was deemed to be sufficient to explain disease susceptibility. Although the commercial potential of individual genomic testing was recognised by the emergent biotechnology industry in the early 1990s, it was not until a decade or so later, post-HGP, that the innovation of ‘gene chips’ (see Glossary) enabled individual diagnostic genomic testing to became commercially viable. Relatively small start-up companies were then able to begin to offer direct-to-consumer (DTC) genomic screening services. The cost of DTC services became increasingly affordable as the gene-chip microarrays could be used on desktop machines. This technology, together with sequencing machines and the appropriate reagents, enabled screening for multiple SNPs in parallel. Overtime the capacity of these chips has grown, and today are able to genotype between 500,000 and 5 million SNPs (NHGRI 2019).

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