Oryza sativa sprang from a single domestication that occurred 8,200–13,500 years ago in China of the wild rice "Oryza rufipogon". A 2012 study, through a map of rice genome variation, indicated that the domestication of rice occurred in the Pearl River valley region of China. From East Asia, rice was spread to South and Southeast Asia. Before this research, the commonly accepted view, based on archaeological evidence, is that rice was first domesticated in the region of the Yangtze River valley in China. The precise date of the first domestication is unknown, but depending on the molecular clock estimate, the date is
Rissoina oryza Rissoina oryza Rissoina oryza is a species of minute sea snail, a marine gastropod mollusk or micromollusk in the family Rissoinidae. The height of the small, white shell attains 2 mm. The shell has an oblong-ovate shape. It is solid, smooth, and shining, The spire is moderately elevated, and rather rapidly tapering. The apex is obtuse. The 6-7 whorls are flatly convex. The body whoprl is rather large, and slightly compressed beneath. The suture is faintly impressed and broadly margined beneath. The rather large aperture is oblique and has a sub-ovate shape. The thick peristome is dilated. The columella is