Transposons (transposable elements), discovered in maize by Barbara McClintock in 1948, are DNA sequences that can change their positions within the genome. Transposition of transposons can introduce mutations in the host genome. Actually, there was a close and astonishing relationship between transposons and the culture of the Edo era. In late Edo, a large number of mutant Asagaos (Japanese morning glory) were isolated, and it became popular to cultivate them; in fact, many mutations were caused by transposons. These mutant Asagaos have been collected by researchers and are currently maintained by a group led mainly by Kyushu University. See the website of National BioResource Project (NBRP) “Asagao” (http://www.shigen.nig.ac.jp/asagao/) for further details. Designed by TRAIS Co., Ltd. (Kobe, Japan)