Several direct-to-consumer genetic testing companies report how much DNA a person has inherited from prehistoric humans, such as Neanderthals (Homo neanderthalensis) and Denisovans. Direct-to-consumer genetic testing companies generally report this information as a percentage that suggests how much DNA an individual has inherited from these ancestors.

Neanderthal DNA and Denisovan DNA in modern humans

Modern humans can have small amounts of Neanderthal DNA, while Denisovan DNA is rarer.

The genomes of modern humans (Homo sapiens) may contain a small amount of Neanderthal DNA. People from African populations typically have little, if any, Neanderthal DNA, and people with a European or Asian background have about 1 to 2 percent. The percentage of Denisovan DNA is highest in the Pacific Island population of Melanesia (4 to 6 percent) and is lower in other Pacific Islander and Southeast Asian populations. Denisovan DNA is found in very low percentages in populations elsewhere in the world.

Neanderthals and Denisovans

Neanderthals lived in Europe and Western Asia from 400,000 to 40,000 years ago.

Denisovans lived in Asia and are distantly related to Neanderthals.

Neanderthals were very early (archaic) humans who lived in Europe and Western Asia from about 400,000 years ago until they became extinct about 40,000 years ago. Denisovans are another population of archaic humans  who were distantly related to Neanderthals and lived in Asia. Much less is known about the Denisovans because scientists have uncovered fewer fossils of these ancient people.

The precise way that modern humans, Neanderthals, and Denisovans are related is still being studied. However, research has shown that modern humans first encountered Neanderthal and Denisovan populations about 50,000 years ago, and that they had children together. As a result, many people living today have a small amount of genetic material from these distant ancestors.

Scientists have sequenced the DNA from Neanderthal and Denisovan fossils that were discovered in Europe and Asia. This genetic information is helping researchers learn more about these early humans. Determining which areas of the modern human genome are shared with archaic humans, and which areas are different, will also help researchers find out what differentiates modern humans from our closest extinct relatives.

The genetic impact of ancient DNA

Direct-to-consumer genetic tests may report on Neanderthal or Denisovan DNA, but the significant of this ancient DNA is still being studied and provides limited information.

Some studies have suggested that certain genetic variations that are inherited from archaic humans may play roles in hair texture, metabolism, immune responses, adaptations to high altitudes, and other characteristics in modern humans. However, most of the archaic DNA found in modern humans tends to regulate gene activity rather than produce proteins. In addition to the percentage of Neanderthal or Denisovan DNA, direct to-consumer genetic testing reports may include information about a few genetic variants inherited from these ancestors that can influence specific traits. The significance of Neanderthal or Denisovan DNA is still an active area of study.

While knowing how much DNA a person has in common with their Neanderthal or Denisovan ancestors may be interesting, these data do not provide practical information about a person’s current health. Having DNA in common with archaic humans says nothing about how “evolved” a person is, nor does it give any indication of strength or intelligence. For now, knowing the percentage of DNA a person inherited from Neanderthal or Denisovan ancestors provides only very limited information.