“Xiao Xiao,” which means “tiny” in Chinese but represents a big victory for scientists as the world’s first cloned mouse from iPS cells, was highly praised by an expert at Britain’s Roslin Institute where the first cloned mammal Dolly was born.

“Most research progresses in small steps. Xiao Xiao represents a jump forward,” said Bruce Whitelaw, head of the Division of Developmental Biology at the Roslin Institute, and editor-in-chief of the journal Transgenic Research.

This is because Xiao Xiao finally proved that iPS cells, the abbreviation of induced pluripotent stem cells, are truly pluripotent. Stem cells are cells that can differentiate into specialized cell types for organisms to grow or repair themselves. In a developing embryo, stem cells can differentiate into all of the specialized embryonic tissues, therefore the embryonic stem cells are called pluripotent.

In 2007, Japanese and American scientists declared at the same time that they induced skin cells into the status of pluripotent independently, which implicated that an adult cell could be reprogrammed to its “embryonic status” and then develops to a full functional creature. Read more…