What’s interesting to me about this find is the linkage, as described below, between this region of the genome and 2 major disease groups.  Pure speculation but this region perhaps is linked to a nutritional function that was beneficial in times of scarcity and lethal now in a world of plenty, as both CVD and diabetes are associated with food abuse.   Link: globeandmail.com:

Two massive and independent studies have discovered a significant
new risk factor for heart disease — a menacing hunk of DNA that half of
all Caucasians carry.

Researchers found the heart risk linked to this genetic trait held
up regardless of whether other well-known signs of susceptibility, such
as high blood pressure, smoking or high cholesterol, are present.

As a result, the finding raises the prospect of a genetic test to
help identify people at high risk of heart disease and measures to
prevent it. It could also lead to a better understanding of the biology
behind the world’s No. 1 killer, since no one yet knows how this
genomic quirk works….

…

Based on research involving 23,000 people in Canada, the United
States and Denmark, scientists found that 50 per cent of Caucasians
carried one copy of an altered stretch of chromosome 9, and as a
result, their risk of developing heart disease rose by 15 to 20 per
cent. A quarter of Caucasians carried two copies and faced an increased
risk of as much as 40 per cent….

…Meanwhile, in a coincidence that has even top geneticists surprised
at the odds, three different groups reported last week that this same
region of chromosome 9 could also raise the risk of Type 2 diabetes.

Francis Collins, director of the U.S. National Human Genome Research
Institute and one of the diabetes investigators, said: "I think this is
a stunner. This is like the seat of the soul of the genome. It seems
like this one place carries all of that weight for two very common and
very dangerous diseases.

"I never would have guessed that we would end up coalescing, zeroing
in on the same 50,000 base pairs out of three billion [chemical units
that make up DNA]…"