Oryza sativa introduced into Korea shortly before or during the Middle Mumun pottery period (circa 850–550 BC) and reached Japan by the final Jōmon or initial Yayoi periods "circa" 300 BC. Rice is the staple for all classes in contemporary Southeast Asia, from Myanmar to Indonesia. In Indonesia, evidence of wild "Oryza" rice on the island of Sulawesi dates from 3000 BCE. The evidence for the earliest cultivation, however, comes from eighth-century stone inscriptions from Java, which show kings levied taxes in rice. Divisions of labor between men, women, and animals that are still in place in Indonesian rice cultivation, can be
Helitron (biology) Helitron (biology) Helitrons are one of the three groups of eukaryotic class 2 transposable elements (TEs) so far described. They are the eukaryotic rolling-circle transposable elements which are hypothesized to transpose by a rolling circle replication mechanism via a single-stranded DNA intermediate. They were first discovered in plants ("Arabidopsis thaliana" and "Oryza sativa") and in the nematode "Caenorhabditis elegans", and now they have been identified in a diverse range of species, from protists to mammals. Helitrons make up a substantial fraction of many genomes where non-autonomous elements frequently outnumber the putative autonomous partner. Helitrons seem to have a major role