Economist Magazine Report on Human Genome

The Economist magazine has a great report on the human genome. Admittedly, it’s challenging reading much of the time.

Many of us following the PSP/CBD genetics project will be familiar with the term GWAS – genome-wide association study. The genetics project is a GWAS taking place on brain tissue of confirmed PSP and CBD patients. This magazine report has a lot to say about the strengths and limitations of GWAS. One of the recent “discoveries” we learned about was that someone needs multiple genetic mutations to develop PSP or CBD; apparently this isn’t a finding specific to PSP or CBD.

Two other things I learned from this special report with regard to GWAS are:

“GWAS has not been a total failure. It has revealed lots of mutations of small effect. On average, though, these add up to only 10% of the total heritability of any given disease. Mendelian effects add about another 1%. The rest, in a phrase that geneticists have borrowed from physicists, is referred to as ‘dark matter’. These mutations appear to be tremendously important, yet neither Mendelian nor GWAS techniques can detect them. Mendelian mutations are noticed because they are rare and powerful. GWAS mutations are seen because, though puny, they are common. The dark matter lies in the middle: too rare for GWAS but not powerful enough to leave a clear Mendelian signal. Bigger GWAS, with more statistical power, may help a bit, but clearly new methods are needed. One will be to deploy whole-genome sequencing more widely, now that it is becoming so much cheaper.”

“It is one thing to find a gene in the genome; it is quite another to find out what it does; and another still to understand whether that knowledge has any medical value. Until these points are dealt with, the drugmaking machine that genomics once promised to become cannot be built.”

Here are links to the two most interesting articles in the report:

“Biology 2.0”
www.economist.com/node/16349358

“Marathon man”
www.economist.com/node/16349422

Robin