In Greek mythology, chimeras are imaginary creatures, often formed by combining parts of several other creatures together into one. Classic examples are centaurs and mermaids. In plants, there are three types of foliage chimeras, sectoral, mericlinal, and periclinal. Sectorial is represented by plants like Philodendron ‘Thai Constellation, which has randomly flecked leaves. Periclinal chimeras are most all plants like hostas, with variegated edges or stable central patterns. Mericlinal chimeras are genetically unstable, but may eventually stabilize into periclinal chimeras. While many chimeras simply affect the color pattern in a leaf, some are tied to other traits. Below is a leaf with a mericlinal chimera. In this case, the leaf variegation is tied to the appearance of the leaf spine. When the leaf edge variegated, it also affects the color and size of the spines. If this were to go completely edged, we would expect tiny spines. If the variegated edge is desirable, we could work on breeding for that trait by cross cutting the core near the desired trait and hope for an offset that would include more consistent edge variegation and select for stability.
Are transposons involved in all three types of foliage chimeras?
Not based on my understanding of transposons. Transposons are usually associated with characteristics like irregular leaf flecking patterns. That said, I don’t profess to be a geneticist, so would welcome comments from those who are such, or those who play one on tv.
Ask Denny Warner the next time you see him? (When I asked home about Cercis “Whitewater” variegation, he answered “Whitewater variegation is controlled by a nuclear gene recessive mutation. First generation offspring from WW crosses show no variegation regardless of direction of cross.” Not clear if “nuclear gene recessive mutation” includes transposons.)
Very interesting.
More posts like this, please!