Brown Eyes: The DOMINANT Trait Hiding a 500,000-Year Secret | History for Sleep

Описание: Brown Eyes: The DOMINANT Trait Hiding a 500,000-Year Secret | History for Sleep

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What secret are your brown eyes still carrying from half a million years ago?

In this Sleepy Time History episode, drift off as we uncover the hidden story behind the world’s most common eye color. From the ancient genes on chromosome 15 (OCA2, HERC2) to the blue-eye mutation that carved light from darkness, we trace how brown eyes became the quiet dominant trait of our species.

Learn how eye color really works, why brown eyes evolved under harsh suns, what ancient DNA reveals about our ancestors, and why your biology teacher was partly wrong about “dominant” and “recessive.” We’ll explore green, hazel, amber, and gray eyes too—and how all of them connect back to deep, dark origins.

If you love calm storytelling, human evolution, genetics, and history you can fall asleep to, this is for you.

Subscribe to Sleepy Time History for more science-based, relaxing history stories you can listen to while you rest.

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Chapters:
00:00 The Color You Never Think About
05:19 A World Painted Brown — The Global Census of Eye Color
15:20 What Makes an Eye Brown — The Biology of Iris Color
24:20 The Genetic Architecture — OCA2, HERC2, and the Switches on Chromosome 15
47:35 Out of Africa — Migration, Bottlenecks, and the First Forks in the Road
59:29 The Blue Eye Mutation — When Light First Carved Color from Brown
1:11:15 Green, Hazel, Amber, and Gray — The Rarer Shades and How They Emerged
1:23:45 Dark Irises Under Harsh Suns — UV, Latitude, and the Adaptive Logic of Brown
1:35:17 Ancient DNA and the Surprises in Ancient Genomes
1:47:53 Stories We Tell About Eyes — Culture, Myth, and the Gaze Across Civilizations
2:01:22 The Dominance Myth — What Your Biology Teacher Got Wrong
2:13:40 Eyes That Change — Babies, Aging, and the Fluidity of Iris Color
2:25:51 Your Eyes as a Time Machine — What Brown Eyes Connect You To
2:37:31 Closing — The Quiet Dominance of Brown

Sources:
Sturm, R.A. & Larsson, M. (2009). “Genetics of human iris colour and patterns.” Pigment Cell & Melanoma Research.
Eiberg, H., Troelsen, J., Nielsen, M., Mikkelsen, A., Mengel-From, J., Kjaer, K.W., & Hansen, L. (2008). “Blue eye color in humans may be caused by a perfectly associated founder mutation in a regulatory element located within the HERC2 gene inhibiting OCA2 expression.” Human Genetics.
Kayser, M., Liu, F., Janssens, A.C.J.W., Rivadeneira, F., Lao, O., van Duijn, K., Vermeulen, M., et al. (2008). “Three genome-wide association studies and a linkage analysis identify HERC2 as a human iris color gene.” American Journal of Human Genetics.
Wilde, S., Timpson, A., Kirsanow, K., Kaiser, E., Kayser, M., Unterländer, M., Hollfelder, N., et al. (2014). “Direct evidence for positive selection of skin, hair, and eye pigmentation in Europeans during the last 5,000 years.” Proceedings of the National Academy of Sciences.
Walsh, S., Liu, F., Wollstein, A., Kovatsi, L., Ralf, A., Kosiniak-Kamysz, A., Branicki, W., & Kayser, M. (2013). “The HIrisPlex system for simultaneous prediction of hair and eye colour from DNA.” Forensic Science International: Genetics.

Note on Process & Accuracy:
Every story on this channel begins with a deep respect for history. We act as directors and editors, using AI tools to help research and draft the script while we shape the narrative and verify facts. The narration comes from a digital replica of a professional voice actor, and the images are individually crafted artistic impressions using AI. Even with these tools, creating a story of this depth still takes hours of work.

Please note that while the narrative is thoroughly based on historical research, its primary purpose is storytelling for entertainment and relaxation. As such, it is not intended to be used as a formal academic or scientific source. Thank you for your trust and support.