Tufts of hair rescued from the permafrost in Greenland and then tucked away in a basement in Denmark for more than 20 years have given scientists their first glimpse into the genetics of an ancient human.
Eske Willerslev and Morten Rasmussen of the Centre for GeoGenetics at the Natural History Museum of Denmark and the University of Copenhagen, along with an international team of collaborators, have sequenced 80% of the genome of a man from the Saqqaq Culture who walked the earth about 4,000 years ago. By comparing this ancient DNA sequence to what is known about the genetics of modern humans, the researchers were able to piece together a picture of what the man they call Inuk (“human” or “man” in Greenlandic) likely looked like, where his people came from, and how he’s related to modern populations. The results were published online today in the journal Nature.
Inuk’s DNA revealed that he had type A+ blood. He likely had brown eyes and thick, dark hair. His skin was probably not the light color found in modern day Europeans. Inuk’s earwax was dry and he had shovel-graded front teeth, both characteristics common in Asian and Native American populations. Several of the genetic variants he carried suggest that he had a metabolism and body mass well-suited to cold climates. The researchers even found that Inuk’s genetics are indicative of an increased risk of baldness.
“Because we found quite a lot of hair from this guy, we presume he died quite young,” Willerslev said in a press briefing.
Analysis of Inuk’s Y chromosome revealed that his paternal haplogroup is Q1a, which is commonly found among Siberian and Native American populations. Previous analysis by the same research group had revealed that Inuk’s maternal haplogroup, determined by his mitochondrial DNA, is D2a1. This same lineage is commonly found in modern-day Aleuts of the Commander Islands in the Bering Sea and the Siberian Sireniki Yuits (Asian Eskimos).
Since discovery of the remains of the Saqqaq Culture in the 1950s, there has been disagreement over how these people were related to others that crossed the Bering Strait into the New World. By analyzing Inuk’s DNA and comparing it to modern populations, the researchers determined that the Saqqaq are most closely related to the Nganasans, Koryaks and Chukchis of Siberia. The long-gone Saqqaqs most likely left Siberia for the New World about 5,500 years ago, independently from the ancestors of present-day Native Americans and Inuit.
Now that his team has shown that full genome sequence analysis of ancient samples is feasible, Willerslev expects that there will be an explosion of work in the field. He says that sequencing of DNA from South American mummies could help illuminate the population history and genetic diversity of Native Americans from before the arrival of Europeans. Willerslev also suggests that sequencing ancient human DNA could reveal when certain genetic diseases become prevalent in different populations.
Do you share genetic characteristics with Inuk? The table below lists the SNPs the researchers used to come up with their physical description of the ancient man. SNPs currently covered by 23andMe are linked to the Browse Raw Data feature, where Complete Edition customers can check their own genotypes. Inuk’s genotype at each SNP is presented in the format used on the 23andMe website, which may not match the original paper. The notes column lists 23andMe content related to each trait and/or SNP.
|Blood type – Not type O*||rs8176719||II||This SNP is part of the ABO blood type lab health lab.|
|Blood type – Type A1||rs8176750||II|
|Brown eyes||rs12913832||AA||This SNP is reported on in the Eye Color Trait Report.|
|Not European light skinned||rs1426654||GG|
|Baldness||rs1385699||T||A different SNP is reported in the Baldness Research Report.|
|Baldness||rs6152||G||Both baldness SNPs are on the X chromosome. Males like Inuk have only one copy.|
|Higher percentage fat mass||rs5746059||AA|
|Dry earwax||rs17822931||TT||This SNP is reported on in the Earwax Type Trait Report.|
|Thick hair and shovel-graded teeth||rs3827760||GG||This SNP is reported on in the Hair Thickness Research Report.|
|Cold adaptation||rs1042522||GG||See previous blog posts about this SNP’s relation to winter temperatures and colorectal cancer.|
* The genotype the study authors listed for this SNP (which was originally listed in this tabel) actually indicated that Inuk would have had type O blood. We contacted the authors and they confirmed that this was simply a typo. The table now reflects Inuk’s true genotype.