Although researchers have first fully sequenced the human genome more than a decade ago, we’re still learning about all of its components. One of the sections we need to learn more about is at the center of the chromosome. This area includes some of the oldest sections of DNA, often with information that is inherited from our Neanderthal ancestors.

The idea that modern humans retain Neanderthal DNA isn’t new. Some commercially available genetic testing services even market their ability to identify these genes. However, scientists are continuing to probe the details about how they affect us. From this analysis, they’re learning things about human history that would be impossible to discover through any other method.

Why information is coming to light now

While researchers have known that modern humans retain DNA from some of our oldest ancestors, they’re just beginning to understand specific impacts. That’s because until recently they’ve not been able to analyze enough genetic samples. Now they’ve begun to access to new databases of information, such as the 1,000 genomes project and a tool from the Great Britan called the UK Biobank. Researchers at the Max Plank Institute for Evolutionary Biology and from UC Davis are among the groups using these kinds of tools to make extraordinary finds.

Clues about Neanderthal migration patterns

The most recent revelations to come from the analysis of Neanderthal DNA concerns when our human ancestors began to migrate. This migration analysis was revealed through genetic testing last month of three specimens that lived approximately 120,000 years ago in geographically distinct areas. It indicates that our earliest European ancestors presented with surprisingly similar DNA to the Neanderthal half of a hybrid Neanderthal girl and her fully Neanderthal mother who lived at a later time in Siberia. This finding supports that the time when Neanderthals replaced their predecessors and then migrated may have been as early as 120,000 years ago.

Neanderthal DNA influence on modern humans

At the very least, researchers would expect any DNA impact on modern humans to affect how we look, from the size of our skulls to our height and strength. In reality, one of the surprising things that researchers found is the range of things that Neanderthal DNA can influence in modern humans. For example, it is possible that the way some of us can taste and smell is affected by our ancient ancestors. Another set of scientists have found that genes inherited from our oldest ancestors can influence whether we are likely to smoke, if we are likely to be affected by depression, and even if we’ll be a morning or an evening person.

We don’t know all of our genetic history

While scientists were researching the center area of the gene, they came across some areas that couldn’t be directly traced to a currently known type of human. This potentially indicates the presence of a “ghost species”, something that was also pointed at during studies of human saliva proteins. All of it shows that while we’ve learned quite a lot about who we are and where we came from, we don’t know everything. Filling the gaps in our evolutionary history is an ongoing scientific challenge.

Not everyone has Neanderthal DNA

Because of human migration patterns, not everyone contains Neanderthal DNA. Neanderthals rose in Europe after pre-humans left the African continent and they never returned. As a result, modern humans of purely African descent don’t show any traces of Neanderthal DNA. In another case, the genetics of modern humans with red hair doesn’t appear to show Neanderthal traits, indicating that there were few, if any, red-haired Neanderthals.

No human DNA has been found in Neanderthals

While there has been Neanderthal DNA found in humans, to date there hasn’t been human DNA found in Neanderthals. To look into this further, researchers evaluated Neanderthal specimens that were dated from the same timeframe that humans were known to have moved into their area. The researchers were surprised by this finding and the likelihood that Neanderthals genetically affected humans far more than humans affected them. When presenting their findings, the scientists caution that their sample size remains small. They may uncover new information if and when they obtain a greater pool of research.

How to learn more: DNA research on Neanderthal specimens

As quickly as this research is progressing, one thing that would help it to move quickly would be the availability of a larger number of samples from known Neanderthals. Just as the comparison of multiple samples helped with recent Neanderthal migration analysis, these kinds of samples would allow researchers to make new discoveries as they compare them with others and with the kinds of ancient genes showing up in modern humans.

Scientists are encouraged by the fact that that this kind of research is beginning to appear. Recently, sequencing was reported by a team that evaluated DNA from a 50,000-year female specimen that was found in a cave in Croatia. This work, along with work that was conducted on rare but well-documented specimens found in other places, is providing geneticists with reference points for what they’re seeing in modern man.

Where the research is going next

Future genetic research is set to uncover a lot of things about the origins of current human traits. One of the tools that are likely to help this research are genetic databases like UK Broadbank and detailed research on documented Neanderthal specimens. In addition, as techniques for genetic sequencing improve, scientists will learn more from the stockpiles of information available.

For now, what we already can tell is surprising and awe-inspiring. It allows us to see how the lives of our ancestors are continuing to affect us. We are learning more about ourselves, becoming wiser about where we came from in fascinating ways.