Habitual acts alter genomes.

The researchers were able to pinpoint and confirm that a single base pair mutation in DNA causing an amino acid change in a protein led to non-shattering rice varieties. This slight change in DNA prevented mature rice grains from easily falling from stalks to allow a more effective field harvest. In essence, humans several thousand years ago unknowingly practiced de facto gene selection by planting varieties with this trait.

Shattering in cereal crops refers to grains easily falling off of plants. The shattering trait of the wild forerunners of rice and cereals prevents effective field harvest and is undesirable for cultivation.