Who were the Neanderthals?
Neanderthals were a species of humans called homo Neanderthalensis and are the closest evolutionary relatives to us present-day humans, homo sapiens. They lived across Europe and south-west and central Asia from approximately 400,000 to 40,000 years ago . While it is a common misconception that we evolved from Neanderthals, scientists believe that both species diverged from a common ancestor in the Homo genus approximately 500,000 years ago.
What are the key differences between Neanderthals and modern-day humans?
Neanderthals were shorter and broader than modern humans, with the most distinctive difference being their larger cranium, brow-ridge and nose, as well as broader hips.
While the stereotype is to think of Neanderthals as primitive cave-dwellers, scientists and archaeologists now know that they were very intelligent and were capable of making tools and jewellery. Archeological evidence also suggests they were a social and compassionate species.
Interbreeding between Neanderthals and early modern humans has contributed to present-day genomes, so your DNA may be able to reveal some intriguing similarities with your ancient relatives.
How much DNA do we share with Neanderthals?
While we share some genetic variants with this ancient human species, the total amount of Neanderthal DNA in present day populations is very small; between 0.2 - 4 percent, dependent on an individual’s ancestry. However, there are a number of our modern-day traits which are still influenced by Neanderthal DNA, including sleep patterns, carbohydrate tolerance and sun sensitivity!
Early bird or night owl?
The time we like to sleep and wake-up varies widely in the general population. A gene known to be closely associated with regulating our circadian rhythm, the internal clock which controls our sleep-wake cycle among other functions, is Period Circadian Regulator 2 (PER2) .
The ‘C’ allele at position rs75804782 on this gene has been linked to Neanderthal DNA and is associated with being a ‘night owl’, so the variant you carry at this position in your genome can suggest if your preferred sleep pattern might in part be down to our ancient relatives.
Struggle to get a suntan?
Whether some people easily develop a suntan or find themselves predisposed to burning when exposed to the sun can also, in some cases, be linked to carrying the ‘Neanderthal version’ of certain genes.
Neanderthals had a low tolerance to sun exposure, having lived in Eurasia for thousands of years where there was a relatively low level of sunlight. When they interbred with modern humans, they passed on some of the genetic variants which predispose people to having pale skin and being sensitive to the sun.
The gene BNC2 produces a protein which plays an important role in functions associated with skin colour saturation, facial pigmentation and sun sensitivity. One particular position on this gene, rs10962612, can indicate if an individual’s lack of tolerance to the sun is partly due to carrying the Neanderthal variant.
Individuals who carry the ‘G’ allele at position rs10962612 are said to have the Neanderthal version of the gene, which appears with a frequency of more than 66% in European populations .
Hunter or farmer?
Being able to store energy for longer was an important survival mechanism for Neanderthals, as they weren’t able to know when or where they would get their next meal.
The gene CLTCL1 produces a specific protein involved in glucose (sugar) metabolism. Different variants at position rs1061325 on this gene influence how quickly sugar is removed from the blood and therefore how quickly we use and lose energy .
The ‘T’ version of this gene originates from Neanderthals and indicates a predisposition for cells to hold glucose for longer, resulting in a slower release of energy. This ‘hunter’ variant helped Neanderthals sustain energy through long periods of fasting and can still be seen in approximately 44% of modern-day humans. As high carbohydrate foods are now widely available, carriers of this gene could potentially benefit from reducing processed carbohydrate intake and added sugars.
Conversely, the ‘C’ version of this gene is known to have circulated among farming populations during the agricultural revolution, when higher carbohydrate foods became more readily available, and is associated with a faster removal of glucose from the blood.
While it’s exciting to know some of us carry genetic variants that are an echo of our ancient relatives, it’s also important to remember that the total amount of Neanderthal DNA present in modern day homo sapiens is still very small, ranging from 0.2 - 4 percent, depending on an individual’s ancestry . And while some traits such as sun sensitivity, carbohydrate tolerance and sleep pattern might in part be attributed to Neanderthal heritage, there is also a wide range of other genes and environmental factors that impact these behaviours and preferences.