Epigenetic regulation of transposable elements in the plant kingdom which allows for self-copying) within the coding of the transposon defines class I elements as autonomous or non-autonomous. Class I transposons can take the form of: Curiously, retrotransposons have been discovered to be the predominant form of transpositional element in plants with large genomes, such as maize and wheat, potentially indicating rapid success of this class of transposon in the creation of hybrids, such as wheat, peppermint and, in the distant past, maize. Plant hybridization often creates polyploids, with double, triple, quadruple or more the number of chromosomes present in the parent generation. Polyploid hybrids seem to be particularly susceptible
Owned-and-operated television stations in the United States Corporation's CBS Television Stations subsidiary with the network instead of Fox's UPN-affiliated stations. In fact, two of the former Chris-Craft stations have the distinction of being owned-and-operated stations of two networks: WWOR-TV (the second in the New York City market after sister station WNYW, which has been an O&O of DuMont and Fox), and KCOP-TV (the first and only station in the Los Angeles market), both having been O&Os of UPN and MyNetworkTV. Viacom/CBS sold off several UPN owned-and-operated stations during the network's final five years. Mercury Broadcasting bought Wichita, Kansas' KSCC (channel 36, now KMTW) in 2001 (the station