A genetic variation that may increase a woman's risk of gestational diabetes is widespread today because it was actually beneficial to early agricultural populations, a new study suggests.
Pregnant women who carry two copies of a low-activity form of the gene GIP have higher blood-glucose levels--a marker of gestational diabetes risk--Sheau Yu Teddy Hsu of Stanford University and colleagues report online February 7 in Diabetes. But when the gene's low-activity version first arose somewhere in Eurasia an estimated 8,100 years ago, that same glucose-boosting quality may have helped women maintain their pregnancies during lean times.
The work is important for characterizing how one form of a gene can shape physiology and how evolution may act on that gene, says Joshua Akey of the University of Washington in Seattle.
Hsu and his colleagues have previously reported evidence that the low-activity version of the GIP gene emerged about 8,100 years ago and rapidly became part of the genetic makeup of Eurasians. Today about half of people of European descent carry this newer form of GIP, while 70 percent or more of Asians do. Only about 5 to 10 percent of Africans have the new form, Hsu says. "It arose very fast, so it must have …