Category: General

This is the face of an ancient Eskimo who walked the Earth at the end of the Ice Age 4,000 years ago.

Scientists have unravelled the genome of a Prehistoric human for the first time after studying a clump of hair preserved in permafrost in Greenland.

They used advances in DNA analysis to discover certain characteristics including the colour of his skin and thickness of his hair – and to prove Eskimos originate from Asia and not North America.

The artist’s reconstruction of the man, who has been named “Inuk”, is based on screening for single nucleotide polymorphisms (SNPs). These are points in the genetic code which vary from person to person.

Researchers recovered his DNA from just a dark tuft of hair that was dug up along with primitive stone tools during an archaeological excavation in the Disco Bay ice fjord area of north-west Greenland in 1986.

The hair belonged to a member of the first Eskimos called the Saqqaqs, who lived inland and hunted reindeer.

On the basis of the analysis, the individual was a male.

There are currently very few details known about Inuk’s people due to the fact that little remains from their culture.

But the new findings published in Nature suggest genomic data can now be used to identify physical traits of individuals from extinct cultures even when there are just small amounts of material, such as bones, left.

Differences in eye, hair and skin colour are largely down to SNPs, known by scientists as ‘snips’ – variations in the sequence of letters that make up a single strand of human DNA.

SNPs represent a change of just one letter in the genetic sequence. These changes, or mutations, in our DNA can have important consequences for how the gene gets physically expressed. Everyone has two copies of an SNP.

So there are several possible combinations, some of which are more heavily associated with, for example, blue eyes, than with brown eyes.
Ancient DNA expert Professor Eske Willerslev and colleagues at the University of Copenhagen, analysed more than 350,000 SNPs from Inuk, comparing them with those of people from several surrounding populations to pinpoint his geographical origin.

Professor Willerslev said: ‘The sample provided us with 80 per cent of the genome of a man living in Greenland four thousand years ago. It is comparable in quality to a modern human genome.

‘We can see the man had brown eyes, brown hair and a tendency to baldness. The clump of hair we found suggests he probably died quite young.

‘We can also see he had A-plus blood type. It is a very high quality genome – to our knowledge the only one of an ancient human.’

Surprisingly, Inuk proved to be most closely related to three Old World Arctic populations – the Nganasans, Koryaks and Chukchis of the Siberian far east.

The researchers said they do not know if Inuk was part of the extinct culture that inhabited Greenland four millennia ago.

But they do conclude their work provides evidence of a migration of ancient humans from Siberia into the New World – movement that was independent of other migrations that gave rise to the modern Native American and Inuit communities.

Professor Willerslev said: ‘A single individual may, or may not, be representative of the extinct culture that inhabited Greenland some 4,000 years ago.

‘Nevertheless, we may conclude that he, and perhaps the group that once crossed the Bering Strait, did this independently from the ancestors of present-day Native Americans and Inuit, and that he shares ancestry with Arctic north-east Asians, genetic structure components of which can be identified in many of the present-day people on both sides of the Bering Sea.

The next technical challenge will be to sequence an ancient human genome from material outside the permafrost regions.

‘Although undoubtedly challenging, it will, if successful, take the emerging field of palaeogenomics to yet another level.’

But evolutionary biologists Professor David Lambert and Dr Leon Huynen, of Griffith University in Brisbane, Australia, said it ‘won’t all be plain sailing’ after reviewing the journal.

They said: ‘One big problem is that the majority of ancient human remains are found in temperate and even hot environments.

‘Because the rate of degradation of ancient DNA increases exponentially with temperature, it remains to be seen whether genomic studies of hominin specimens from these regions will recover sufficient DNA to be informative.’

But they added that whatever the case, the latest findings ‘will no doubt stimulate a series of additional studies and provide useful methods for future investigations of human evolution’.
http://www.dailymail.co.uk/sciencetech/article-1250117/Revealed-Face-prehistoric-man-walked-Earth-4-000-years-ago.html