Am. J. Hum. Genet. doi:10.1016/j.ajhg.2009.05.011 (2009)

Genome-wide association studies have been hailed for their ability to find genetic variations that may contribute to disease risk. But assigning meaning to these variations is more difficult. Peter Holmans of the MRC Centre for Neuropsychiatric Genetics and Genomics in Cardiff, UK, and his colleagues have developed an approach that they call ALIGATOR.

They look for gene ontology categories — agreed-upon terms used to define the function and activity of gene products — that regularly pop up in the candidates exposed by genome-wide association, reasoning that many associations in the same category signal functional relevance. For Crohn's disease, which is immunological in origin, overrepresented ontological categories included immune functions, as expected. For bipolar disorder, they included hormone activity and RNA splicing, processes with as yet unknown roles in the condition.