Baltic agriculture led to genetic selection for very light skin

Evidence

Among regions of the globe above 50°–55° latitude (e.g., much of Canada), the area around the Baltic Sea was almost unique in its ability to support early agriculture. Starting around 6000 years ago, a cultural package of cereal crops and agricultural know-how gradually spread from the south and was adapted to the Baltic ecology. Eventually, people became primarily dependent on farmed foods and lacked access to the fish and other vitamin-D-rich food sources that local hunter-gatherer populations had long enjoyed. As a consequence of this combination of living at high latitude and a lack of vitamin D, natural selection kicked in to favor genes for really light skin, so as to maximize whatever vitamin D could be synthesized using UVB light. — Joseph Henrich, The Secret of Our Success, 281

Categorization

• ADDENDUM: Relevant to the trees-as-infrastructure piece only tangentially; more relevant as a clean culture-drives-genes exemplar usable in any of the three published articles as an intro anecdote about culturally-created environments reshaping bodies.
• CANDY: Light skin at the Baltic arose from farming cereal at high latitude cutting vitamin D — a clean, tweetable mechanism.
• XREF: connects to: Equatorial dark skin evolved to block UV light from destroying folate. — Joseph Henrich, The Secret of Our Success: How Culture…, 279; Light-colored eyes exist only because agriculture created selection for pale skin — Joseph Henrich, The Secret of Our Success: How Culture…, 281; Over 100 human genes show likely selection with cultural origins — Joseph Henrich, The Secret of Our Success: How Culture…, 302 (+4 more)

Broader Connections

• Light-colored eyes exist only because agriculture created selection for pale skin #corroborates (0.85) — Joseph Henrich, The Secret of Our Success, 281
• Cultural evolution can create selection pressures stronger than natural ones #expands (0.82) — Joseph Henrich, The Secret of Our Success, 282
• Food plants and humans shape each other’s evolution toward mutual thriving #corroborates (0.82) — Robin Wall Kimmerer, Braiding Sweetgrass, 431
• Over 100 human genes show likely selection with cultural origins #expands (0.80) — Joseph Henrich, The Secret of Our Success, 302
• Cultural economic packages drive genetic differences even between nearby populations #expands (0.78) — Joseph Henrich, The Secret of Our Success, 311
• Cultural and genetic evolution began mutually reinforcing each other around 2 million years ago #expands (0.75) — Joseph Henrich, The Secret of Our Success, 203