Diabetes gene traced back to Neanderthals

A gene variant increases the risk of type 2 diabetes in Latin American populations,
according to a study in Nature.

The risk gene
was discovered when researchers tested samples from over 8,000 Mexican and other
Latin American individuals, of whom nearly half had type 2 diabetes.

The findings
may help to explain why nearly one in six Mexicans has diabetes, whereas the figure
is less than one in ten for people from the USA, despite both populations having
similar levels of obesity. The research suggests that the new gene variant
could account for up to 20 percent of the increased prevalence of type 2
diabetes in Latin Americans.

'To
date, genetic studies have largely used samples from people of European or
Asian ancestry, which makes it possible to miss culprit genes that are altered
at different frequencies in other populations', said Dr José Florez, co-author of
the SIGMA Type 2 Diabetes Consortium study, from Harvard Medical School.

'By
expanding our search to include samples from Mexico and Latin America, we've
found one of the strongest genetic risk factors discovered to date, which could
illuminate new pathways to target with drugs and a deeper understanding of the
disease', he added.

Known as
SLC16A11, the gene variant is present in half of samples from Native Americans and
ten percent from East Asians, but is rare in Europeans and Africans. This
frequency pattern is unusual: humans as a species are thought to have arisen out of Africa so nearly
all common human genetic variants are present in African populations.

The SLC16A11
gene risk variant was also found in a newly sequenced Neanderthal genome in
Siberia by researchers from the Max Planck
Institute for Evolutionary Anthropology. Further analysis suggests that the
SLC16A11 risk variant was introduced into early modern humans by interbreeding
with Neanderthals.

Professor David Altshuler,
co-senior author and Harvard Medical School Professor, said: 'One
of the most exciting aspects of this work is that we've uncovered a new clue
about the biology of diabetes. We are now hard at work
trying to figure out what is being transported, how this influences triglyceride
metabolism and what steps lead to the development of type 2 diabetes'.

Ultimately, the researchers hope
that this discovery will lead to improved risk assessment and possibly
therapies for type 2 diabetes.