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 WB); WWOR-TV (channel 9) in Secaucus, New Jersey (part of the New York City market) and KCOP-TV (channel 13) in Los Angeles were de facto O&Os prior to Viacom's buyout of Chris-Craft's stake in UPN, while WPWR-TV (channel 50) in Chicago was an affiliate of UPN throughout the network's run (and would not be co-owned with the two other larger-market stations until after Fox purchased it from Newsweb Corporation in 2002). In September 2006, these stations became O&Os of MyNetworkTV, which was created in response to The CW's decision to affiliate stations owned by Tribune Broadcasting and network part-owner CBS