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The most common variegation encountered in cultivated plants is not naturally genetic, however, but due to aberrant mutations in the chromosomes of the growing, or meristematic tissues. Seed from these plants will usually not germinate into another variegated plant, though in some situations, the frequency of variegation is definitely increased over the random norm. In most of these variegated cultivated plants, the variegation mutation is bred for by selecting for the best foliage or flower variants. This is done by division or other forms of vegetative propagation (such as growing new plants from stem cuttings... root cuttings will usually not result in any more variegated plants than one would encounter randomly). Many of these mutated variants are consistent from generation to generation, but others are completely random. These non-natural mutations are known as chimeras, or the combining of two different chromosomal make-ups in a single organism (in this case, cells that do not produce pigment alongside with those that do). These can be fairly consistent from leaf to leaf, or sometimes the variegation will show up randomly on the plant with some variegated leaves or branches here and none there.
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