Chinese rice farmers 10,000 years ago were early pioneers of modern genetic breeding. Like modern breeders they seemed to realise that shorter plants would produce higher yields, and unwittingly selected for mutations in a gene that shrinks rice stems: the stalkier plants produce more grain without falling over.

Masanori Yamasaki of Kobe University in Japan looked at sticky rice Oryza sativa japonica. He found two mutations in the SD1 gene that did not exist in a wild variety or in long-grain rice. What’s more, the DNA around SD1 varied less, even though over 100 other chunks in the genome did not.

That suggests SD1 was under strong pressure to be conserved 10,000 years ago, when both sticky and long-grain rice were being domesticated. Yamasaki thinks farmers growing the first sticky rice drove this change to get a better harvest. In doing so, they kicked off an early “green revolution”: the SD1 gene played a key role in last century’s efforts to boost yields and feed the booming global population.

Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1019490108