Agriculture emerged independently around the world beginning 12,000…

[Richard Kielbasa]

Agriculture emerged independently around the world beginning 12,000 years ago

Humans losing the ability to digest milk (i.e. lactase production halting around age 2-5) is an ancient evolutionary signal meant to motivate hunting and gathering.

Noise —> “In populations that domesticated cattle (Northern Europeans, East Africans, the Middle East), mutations that kept lactase production into adulthood were massively advantageous and swept through those populations in just a few thousand years. This is one of the strongest signals of recent natural selection in the human genome.”

Hunter gatherers were opportunistic i.e. they ate what they found.

Noise —> a year’s single harvest had to sustain early farming communities until the next. This necessitated rationing food grain for 10-12 months while holding the best stock back as seed grain. Failure of process spiraled into famine.

Agriculture selected against chaos, for process.

By sequencing Y-chromosomes and mitochondrial DNA, we can reconstruct the effective population size of males and females over time.

About 5,000–7,000 years ago, Y-chromosome diversity collapsed to 1 male reproducing for every 17 females

The bottleneck is temporally staggered across geographies, relative to the emergence of agriculture in each:

“In the Near East and Anatolia, where farming emerged earliest, the bottleneck appears earlier. In Europe, it shows up after the Linearbandkeramik (its first major farming culture) but before centralized Bronze Age polities. In East Asia, a similar pattern appears on its own timeline.”

—> Agriculture enabled hierarchy, which proved resilient.

High-status males monopolized reproductive access and sent low-status males to die for their wars.

Men were specifically bred post-agriculture for organized society’s hierarchical competition while women were insulated from the genetic slaughter.