“We can’t tell from this study if the SNPs themselves are causing the disorders through changing the way the genes work, or if it is something nearby on that same DNA segment,” says Tayaza Fadason, a PhD student at the Institute in the research team.
“But it is clear that these SNPs we have identified are markers of DNA segments that are somehow altering the functioning of the genes they come into contact with.”
Says Dr O’Sullivan: “The other remarkable finding was that many of the regulatory SNP-gene connections we pinpointed affect body tissues not usually thought of as driving obesity or type-2 diabetes – breast tissue, brain tissue from the cerebellum, skin and blood, the fat that sits just beneath the skin. On the other hand, while visceral fat has a big contribution to diabetes, we found few SNP-gene connections in that tissue.
“This means researchers need to broaden their hunt for genetic drivers of obesity and diabetes beyond the usual suspects.”
It also lends weight to a new way of thinking about DNA and the human genome that is gaining traction among geneticists, which recognises that there’s more to genetics than the sequence of genes, he says. “We also need to understand the other forms of information in DNA – including how it’s folded - that affect how genes are read and used.”
The research team also included Cameron Ekblad and William Schierding from the Liggins Institute, and John Ingram from The New Zealand Institute of Plant and Food Research.
The team is currently looking at SNP-gene connections’ role in type-1 diabetes, muscle wasting and the relationships between other medical disorders.
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Associated article:
Frontiers in Genetics: Physical interactions and expression quantitative traits loci identify regulatory connections for obesity and type 2 diabetes associated SNPs
KEY POINTS
- Many people with obesity also develop type 2 diabetes, but until now, the genetic link between these two conditions has been unclear
- Using new techniques, researchers from the Liggins Institute and New Zealand Institute of Plant and Food Research have identified pieces of the DNA, called SNPs, that change the activity of far-off genes through being brought into contact with them because of how DNA is tightly coiled into the cell nucleus
- These regulatory SNP-gene connections suggest that a far wider range of tissues may play a role in obesity and diabetes than the “usual suspects” that scientists currently focus on