Oryza sativa times can be found in the Cordillera Mountain Range of Luzon in the provinces of Apayao, Benguet, Mountain Province and Ifugao. The Banaue Rice Terraces (Tagalog: "Hagdan-hagdang Palayan ng Banaue") are 2,000- to 3,000-year-old terraces that were carved into the mountains by ancestors of the Batad indigenous people. The terraces are commonly thought to have been built with minimal equipment, largely by hand. The terraces are located about 1,500 m (5,000 ft) above sea level and cover 10,360 km (about 4,000 mi) of mountainside. They are fed by an ancient irrigation system from the rainforests above the terraces. Evidence of
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