Professor David Reich of Harvard Medical School, the lead author of
the study, said: 'Now that we can estimate the probability that a particular
genetic variant arose from Neanderthals, we can begin to understand how that
inherited DNA affects us'.
The researchers compared the genomes of 1,004 people of European and
Asian descent with Neanderthal DNA from a 50,000-year-old toe bone found in a
Siberian cave. These genomes were also compared to
those of 176 West Africans. Ancestors of people from that part of the world are
thought never to have interbred with
In contrast, between two
percent and four percent of the modern non-African genome is considered to be a
result of ancient Homo sapiens interbreeding with Neanderthals.
The researchers in this study found
that Neanderthal DNA is not evenly distributed throughout the genome - some
areas are particularly rich, whereas in other areas it is almost entirely absent.
Neanderthal DNA was found in very low quantities in regions of the X chromosome and in testes-specific genes, for example.
However a number of genetic variants
inherited from Neanderthals were linked to diseases, especially autoimmune disorders such as lupus, biliary cirrhosis (an autoimmune disease of the liver), Crohn's disease and type 2 diabetes.
One question the scientists are considering is whether
our ancient relatives also had these diseases or whether the variants only impact
health in a modern genetic setting. Currently, says Dr Sriram Sankararaman, one of
the study's scientists, 'we don't have the fine knowledge of the genetics of
Neanderthals to answer this'.
might come with further research. In a statement, the scientists say they are now
searching for Neanderthal mutations in a 'biobank containing genetic data from
half a million Britons', presumably UK Biobank.