This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Oryza rufipogon is an ordinary-looking wild grass found today in parts of China, India and Southeast Asia. More than 8,000 years ago, people living in the Lower Yangtze Valley began cultivating it.
Like any other wild grass, O. rufipogon releases its seeds to the ground when ready to propagate new plants. Perhaps inadvertently at first, people selected rare individual plants that failed to release their seeds, kept an upright posture and had other traits that made it easier to harvest their seeds for food. Over time, people brought together a combination of traits in the cultivated grasses that made them distinct from their wild ancestors—an act of genetic modification through selective breeding that long preceded the establishment of genetics.
The crop they created is recognized today as Oryza sativa subspecies japonica, or domesticated Asian rice. It's one example of how, around the end of the last ice age 11,700 years ago, people all over the world independently started directing the evolution of local crops. This process had far-reaching consequences.
From the chinampas—the floating maize or corn gardens—of the Aztecs in Mesoamerica to rice paddies in East Asia to wheat fields in the Fertile Crescent in Southwest Asia, domesticated crops supported the establishment of large, stationary populations through mass labor and food surpluses, paving the way for the emergence of modern societies. Crop domestication can stake a claim to being among the most pivotal technological advances in human history. Societal impact aside, domestication is a unique evolutionary process driven by a domesticator species—such as humans—exerting control over the reproductive success of a domesticated species, such as rice.
Domesticated crops are therefore powerful systems for studying recent, rapid adaptation. I'm an evolutionary biologist based in Michael Purugganan's lab at New York University, where we use genomics to study the processes of rice's domestication and subsequent dispersal. We're interested in when and how the crop spread from its center of domestication in the Lower Yangtze region of modern-day China, and what genetic changes underpinned domestication and allowed adaptation to new environments.
It is clear that crop domestication entails genetic change. But how much genetic change constitutes complete domestication? Are there a small number of dramatic changes in key genes, or hundreds of small changes across the genome?
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