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About half a million years ago, Homo sapiens were not the only species on Earth that were walking upright, hunting, or using tools. Many species coexisted that are grouped into a broad category of “archaic humans”. Homo sapiens eventually became the dominant species, however, they did interbreed with other human species. This means that modern-day humans are sharing some DNA with these archaic humans.
The mating of humans with Neanderthals around 50,000 years ago introduced Neanderthal genes into the human DNA. These new variants of DNA may have helped humans that migrated out of Africa survive better in new environments. Data suggests that 1% - 4% of genes in present-day humans are made of Neanderthal DNA. Studying these variations of human DNA can help give scientists an insight into the differences between Neanderthals and humans and how humans with these DNA variants evolved as time went on. Mutations due to interbreeding with Neanderthals can be associated with different traits in skin tone, hair color height, and even how chemical reactions and the immune system work in our bodies. However, questions still remain on how much these genes are actually actively influencing the traits of modern humans. A study in Iceland suggested that Neanderthal mutations actually had a limited effect on modern humans as the natural elimination of less advantageous traits occurred over time. Finding out how Neanderthal DNA has contributed to specific characteristics remains challenging and, therefore, scientists are looking further into trying to break down the impact of Neanderthal variants on complex characteristics.
Researchers from multiple institutions have now developed a new set of computational genetic tools to find out what the effect of breeding between humans and Neanderthals is. The tool was created with the purpose of investigating the level of contribution Neanderthal DNA has to modern human traits and if this is at the same level as normal human DNA. An analysis of the data gained from this tool has allowed researchers to identify around 235,000 variants in human DNA that are likely to have been gained from Neanderthals. Out of these 4,303 are believed to influence 47 characteristics of modern humans. Results have also suggested that the level of contribution of Neanderthal DNA has reduced over time as modern human DNA has become more dominant.
This software is now available for download and use free of charge by other scientists interested in further research. There were limitations to this research due to deficiencies in the current availability of data about human DNA and statistical methods that may not be precise enough. The sample was limited to white and British individuals. Future research using a larger and more diverse sample can also be used to replicate and validate these findings. Overall, this study has used more precise statistical methods than previous studies and the tool they have created is important to help understand how interbreeding with archaic humans still shapes the biology of modern humans. Furthermore, it is important to understand if these characteristics are beneficial or detrimental.
Works Cited
“CK12-Foundation.” Flexbooks.ck12.org, 19 Nov. 2018, flexbooks.ck12.org/cbook/ck-12-college-human-biology-flexbook-2.0/section/7.6/primary/lesson/neanderthals-and-other-archaic-humans-chumbio/. Accessed 30 June 2023.
Science Daily. “Lingering Effects of Neanderthal DNA Found in Modern Humans.” ScienceDaily, 8 June 2023, www.sciencedaily.com/releases/2023/06/230608195656.htm. Accessed 30 June 2023.
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