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 and CBS' KMOX-TV (channel 4, now KMOV) in St. Louis. As a result of a revision to the FCC's media ownership rules in 1999, a company can now own any number of television stations with a combined market reach of less than 39% of the country, but cannot own two of the four highest-rated stations in any market. Still, O&Os in the United States are primarily found in large markets such as New York City, Los Angeles and Chicago, among others. Despite that, network-owned stations can still be found in smaller markets (for example, KFSN-TV (channel 30) in Fresno, California