Tea plants are native to East Asia, and probably originated around the meeting points of the lands of north Burma and southwest China.[24] Statistical cluster analysis, chromosome number, easy hybridization, and various types of intermediate hybrids and spontaneous polyploids indicate that likely a single place of origin exists for Camellia sinensis, an area including Assam state of India, northern part of Burma, and Yunnan and Sichuan provinces of China.[24] Tea drinking may have begun in the Yunnan region during the Shang Dynasty in China, when it was used for medicinal purposes.[6] It is also believed that in Sichuan, "people began to boil tea leaves for consumption into a concentrated liquid without the addition of other leaves or herbs, thereby using tea as a bitter yet stimulating drink, rather than as a medicinal concoction