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Genes that affect diseases and other traits may be scattered across genome

Biomedical researchers tend to envision genes for traits from height to Alzheimer’s disease as being clustered in a limited number of pathways.

Two assumptions have guided this perspective: that specific traits or diseases are influenced by a few dozen genes and that this limited menu of genes tends to be governed by molecular pathways known to be associated with the disease.

For example, researchers might look for genes promoting diabetes in molecular pathways associated with sugar metabolism. Similarly, a hunt for genes that increase the risk for Alzheimer’s would focus on pathways active in the brain.

But while those assumptions make intuitive sense, Jonathan Pritchard, PhD, professor of genetics and of biology, said he has found that data don’t always agree.

Recently, Pritchard and colleagues (shown above) published a paper in Cell suggesting that the bulk of the inheritance of complex traits comes not from those few dozen “core genes” but from thousands of gene variants scattered across the genome. Graduate student Evan Boyle and postdoctoral scholar Yang Li, PhD, share lead authorship.

As I reported in a news release:

The gene activity of cells is so broadly networked that virtually any gene can influence disease, the researchers found. As a result, most of the heritability of diseases is due not to a handful of core genes, but to tiny contributions from vast numbers of peripheral genes that function outside disease pathways.

Any given trait, it seems, is not controlled by a small set of genes. Instead, nearly every gene in the genome influences everything about us. The effects may be tiny, but they add up.

It's an interesting perspective, one that is sure to spur a host of inquiries.

Previously: New technique offers glimpse at human evolution in actionGenetics: A look back at the first 100 yearsComputing our evolution
Photo by Steve Fisch

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