NCBI has just announced a handy new browser for examining regions of the genome associated with common diseases and other traits through genome-wide association studies (GWAS). As a side-effect, you can generate maps showing the distribution of disease associations across the genome. The plot below shows just how far we have come in finding the genetic regions underlying complex traits: even using a stringent threshold (P values less than 10-8) there are still 2,730 markers that have been uncovered so far, and they're smeared all across the genome:
There are some clear patterns in the smear - for instance, the striking cluster of associations towards the left-hand end (short arm) of chromosome 6 marks the HLA region, packed full of highly variable immune genes) - but overall the message is that we're finding genes associated with human traits all over the place. And there's plenty more to come: over the next few years, as increasing patient sample sizes and new sequencing technologies give us access to variants with smaller effects on risk and with lower frequencies in the populations, this map will become increasingly crowded.
