Human geneticists have reached a private crisis of conscience, and it will become public knowledge in 2010. […]
In 2010, GWAS [“genome-wide association studies”] fever will reach its peak. Dozens of papers will report specific genes associated with almost every imaginable trait—intelligence, personality, religiosity, sexuality, longevity, economic risk-taking, consumer preferences, leisure interests and political attitudes. […]
GWAS researchers will, in public, continue trumpeting their successes to science journalists and Science magazine. They will reassure Big Pharma and the grant agencies that GWAS will identify the genes that explain most of the variation in heart disease, cancer, obesity, depression, schizophrenia, Alzheimer’s and ageing itself. Those genes will illuminate the biochemical pathways underlying disease, which will yield new genetic tests and blockbuster drugs. Keep holding your breath for a golden age of health, happiness and longevity.
In private, though, the more thoughtful GWAS researchers are troubled. They hold small, discreet conferences on the “missing heritability” problem: if all these human traits are heritable, why are GWAS studies failing so often? The DNA chips should already have identified some important genes behind physical and mental health. They simply have not been delivering the goods. […]
Why the failure? The missing heritability may reflect limitations of DNA-chip design: GWAS methods so far focus on relatively common genetic variants in regions of DNA that code for proteins. […] At worst, each human trait may depend on hundreds of thousands of genetic variants that add up through gene-expression patterns of mind-numbing complexity.
We will know much more when it becomes possible to do cheap “resequencing”—which is really just “sequencing” a wider variety of individuals beyond the handful analysed for the Human Genome Project. […] The missing heritability problem will surely be solved sooner or later.
The trouble is, the resequencing data will reveal much more about human evolutionary history and ethnic differences than they will about disease genes. Once enough DNA is analysed around the world, science will have a panoramic view of human genetic variation across races, ethnicities and regions. We will start reconstructing a detailed family tree that links all living humans, discovering many surprises about mis-attributed paternity and covert mating between classes, castes, regions and ethnicities.
We will also identify the many genes that create physical and mental differences across populations, and we will be able to estimate when those genes arose. Some of those differences probably occurred very recently, within recorded history. […]
If the shift from GWAS to sequencing studies finds evidence of such politically awkward and morally perplexing facts, we can expect the usual range of ideological reactions, including nationalistic retro-racism from conservatives and outraged denial from blank-slate liberals. The few who really understand the genetics will gain a more enlightened, live-and-let-live recognition of the biodiversity within our extraordinary species—including a clearer view of likely comparative advantages between the world’s different economies.