Swedish DNA and the Evolution of Blond Hair…

Swedish DNA and the Evolution of Blond Hair…

Chapters:
0:00 Intro
0:26 Genetics & Origin Blond Hair
1:26 How Old in Sweden?
4:26 The Eastern Link...
6:05 Get Member-Only Videos
6:18 Why Blond Hair?

Look at this table. These are the countries with the most people with natural blond hair in the world. As you can see, Sweden is number 1, with over 70% of Swedes having this hair color. Yet globally, only around 2% of people are natural blonds. So why do so many Swedes have blond hair? Has this always been the case? And what factors have been involved in the evolution of blond hair in Sweden, and more broadly?

Now blond hair in Europeans is primarily caused by genetic mutations that reduce the amount of eumelanin. And a key driver of this change comes from a mutated allele, rs12821256, of the KITLG gene. As an interesting side note, some Melanesian populations also have natural blond hair. But this is caused by a completely different genetic mutation than the one found in Europeans, and many others around the world. It’s fascinating though how the same trait can evolve independently in different parts of the world.

But did this Eurasian blond hair mutation originate in Sweden? Well ancient DNA shows that the oldest fossil known to carry this allele of the KITLG gene, is a 17,000 year old Ancient North Eurasian specimen from Afontova Gora in Southern Siberia. So the origin of blond hair was most likely in Siberia, or around this area, not in Sweden. But how did this trait first arrive in Scandinavia then, and who was the first person with blond hair in ancient Sweden?

Now we know that the earliest populations in this region after the ice age were Mesolithic hunter-gatherers, often called Scandinavian Hunter-Gatherers (SHG). And this group was created from the mixing of Western Hunter-Gatherers moving north, and Eastern Hunter-Gatherers moving west. Now we know that WHG largely had dark brown hair and blue eyes, with the genes for blond hair essentially absent from them.

Sources:

The Origin of Blond Afros in Melanesia | Science | AAAS

Mathieson, I., Alpaslan-Roodenberg, S., Posth, C. et al. The genomic history of southeastern Europe. Nature 555, 197–203 (2018). https://doi.org/10.1038/nature25778

Mathieson, I., Lazaridis, I., Rohland, N. et al. Genome-wide patterns of selection in 230 ancient Eurasians. Nature 528, 499–503 (2015). https://doi.org/10.1038/nature16152

S. Perretti, et al. Inference of human pigmentation from ancient DNA by genotype likelihoods, Proc. Natl. Acad. Sci. U.S.A. 122 (29) e2502158122, https://doi.org/10.1073/pnas.2502158122 (2025).

Frost (2006), Evolution and Human Behavior – sexual selection hypothesis for European hair/eye color diversity researchgate.netresearchgate.net

Margaryan, A., Lawson, D.J., Sikora, M. et al. Population genomics of the Viking world. Nature 585, 390–396 (2020). https://doi.org/10.1038/s41586-020-26...

Sci-News (2020) – Viking age DNA findings by Margaryan et al. sci.news
Blonde hair evolved more than once | Nature

European Hunter-Gatherers Had Dark Skin, Blue Eyes | Sci.News

Neolithicarch.com – summary of blond hair allele origins with references to Lazaridis (2022) and Reich (2018 ) neolithicarch.com

Blonde is the UK's number 1 dyed hair colour of choice

ABC News (2006) – report “Cavemen Preferred Blondes” on Frost’s study abcnews.go.com

Celtic History Decoded - Finnish DNA: What is the Genetic History of Finland?

Creative Commons Imagery:

पाटलिपुत्र DalGobboM Skin colour and vitamin D: An update - Andrea Hanel, Carsten Carlberg Skin colour and vitamin D: An update - Hanel - 2020 - Experimental Dermatology - Wiley Online Library Creative Commons Attribution-Share Alike 4.0 International license. Deed - Attribution-ShareAlike 4.0 International - Creative Commons

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Ylwa Moritz File:Southwest Sweden hunter-gatherer Burial XXII (5000 BCE, reconstruction, Trelleborg Museum).jpg - Wikimedia Commons Creative Commons Attribution 4.0 International license. Deed - Attribution 4.0 International - Creative Commons

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Swedish Ancestry – Swedish DNA – Blond Hair – Blond Hair Origin – Blonde Hair – Scandinavia – Sweden – Genetics – Eastern Hunter Gatherers – History

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