To search for genetic variants associated with adult height, researchers performed a complex genetic analysis of more than 100,000 individuals. "We set out to replicate previous genetic associations with height and to find relevant genomic locations not previously thought to underpin this complex trait" explains Dr. Brendan Keating, also from The Children's Hospital of Philadelphia. The authors report that they identified 64 height-associated variants, two of which would not have been observed without such a large sample size and the inclusion of direct genotyping of uncommon single-nucleotide polymorphisms (SNPs). A SNP is a variation in just one nucleotide of a genetic sequence; think of it as a spelling change affecting just one letter in an uncommonly long word.
Note the number of height-associated variants. The reason it has taken so long to make use of genetic sequencing data is that many different variants each contribute to height, personality, disease incidence, and other attributes and risks. Since each variant contributes so little a large number of subjects must be used to detect the various small contributors.
I want the search for the meaning of genetic variants to go much faster. With prices for personal genetic testing getting pretty cheap I'm intrigued by the prospect that lots of individuals can pay affordable prices to get themselves tested and also enter health info onto a web form to participate in scientific research into the meaning of genetic variations. This holds the promise of greatly lowering the cost of research while speeding up the rate of discoveries.
The first phase of the study includes development and validation of web-based surveys to assess the drug side effects and drug effectiveness experienced directly by 23andMe's customers. During the second phase, the research team will determine whether this approach enables them to replicate previously known associations between response to these three classes of drugs and variation within two genes: CYP2C9 and CYP2C19. 23andMe's research team will also search for previously unknown genetic factors associated with response to these classes of drugs, taking into consideration a broad range of non-genetic factors such as age, sex, and body-mass index, among others.
In previous studies, 23andMe has demonstrated that self-reported information from customers yields data of quality comparable to that gathered using traditional research methods.
23andMe's new gene chip tests about 1 million locations on genes where variations occur. Suppose a few hundred thousand people sign up for their service and then also enter in lots of information (e.g. height, eye color, hair color, weight, assorted other physical measurements, history of allergies, asthma, injuries, drug reactions, and other events and maladies). The influences of large numbers of genetic variants could be discovered.
Lots of discoveries are waiting to be made using cheap gene chips to collect data on lots of known single letter genetic variants. After that flood of genetic data comes an even bigger flood. While sequencing the first complete genome took years and hundreds of millions of dollars the costs have now fallen into the tens of thousands (if not lower) per genome. With these low costs the rate of full genome sequencing has now reached hundreds per quarter and therefore over one thousand per year. We can expect the rate to go up by more orders of magnitude.
Complete Genomics said last week that it anticipates sequencing more than 300 human genomes in the fourth quarter of 2010.
Full genome sequencing allows identification of extremely rare genetic variants and also the measurement of large copy variations and other genetic variants not easily captured by gene chips. But data the gene chips alone, used by hundreds of thousands and even millions of people and combined with personal data, will allow scientists to identify at least tens of thousands of genetic variants that influence who we are.
|Share |||Randall Parker, 2010 December 30 10:45 PM Human Population Genetics|