Oryza sativa Italy. In northern Iran, in Gilan province, many "indica" rice cultivars including 'Gerdeh', 'Hashemi', 'Hasani', and 'Gharib' have been bred by farmers. Mainstream archaeological evidence derived from palaeoethnobotanical investigations indicate dry-land rice was introduced to Korea and Japan sometime between 3500 and 1200 BC. The cultivation of rice then occurred on a small scale, fields were impermanent plots, and evidence shows that in some cases domesticated and wild grains were planted together. The technological, subsistence, and social impact of rice and grain cultivation is not evident in archaeological data until after 1500 BC. For example, intensive wet-paddy rice agriculture was
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