By Paul RinconScience editor, BBC News website
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A gene variant that seems to increase the risk of diabetes in Latin Americans appears to have been inherited from Neanderthals, a study suggests.
We now know that modern humans interbred with a population of Neanderthals shortly after leaving Africa 60,000-70,000 years ago.
This means that Neanderthal genes are now scattered across the genomes of all non-Africans living today.
Details of the study appear in the journal Nature.
The gene variant was detected in a large genome-wide association study (GWAS) of more than 8,000 Mexicans and other Latin Americans. The GWAS approach looks at many genes in different individuals, to see whether they are linked with a particular trait.
People who carry the higher risk version of the gene are 25% more likely to have diabetes than those who do not, and people who inherited copies from both parents are 50% more likely to have diabetes.
The higher risk form of the gene – named SLC16A11 – has been found in up to half of people with recent Native American ancestry, including Latin Americans.
Drug hope
The variant is found in about 20% of East Asians and is rare in populations from Europe and Africa.
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This could illuminate new pathways to target with drugs and a deeper understanding of the disease”
Prof Jose FlorezHarvard Medical School
The elevated frequency of this variant in Latin Americans could account for as much as 20% of these populations’ increased prevalence of type 2 diabetes – the origins of which are complex and poorly understood.
“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 co-author Jose Florez, associate professor of medicine at Harvard Medical School in Massachusetts.
“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.”
The team that discovered the variant carried out additional analyses, in collaboration with Svante Paabo of the Max Planck Institute for Evolutionary Anthropology.