I have read a number of papers regarding the causes of variegation, and it seems that while chimeral variegation is relatively well researched, research on non-chimeral variegation such as tora-fu as well as certain types of shima is almost non-existant.
On top of that, most of the research that has been done, has been done on on arabidopsis and other dicots. Because of the different way cells are arranged in the leaves in dicots, it makes it really difficult to really compare neo variegation with the named types of variegation seen in the arabidopsis studies. There are a bunch studies on iojap corn, but I haven't really been able to link that to any specific type of variegation in neos either.
As for the paper regarding using Neos as a model species, I have read that before, and while interesting to read, doesn't really delve into the whys of the different flower forms, and just shows a number of different types (it's not even comprehensive
). It's a good start, but I wish there was more.
And even beyond variegation and flowers themselves, there are other characteristics that would make neos interesting to research; the causes of different types dwarf leaves, what causes a tsuke to be one shape or another, what causes a plant with no tsuke, what causes characteristics like sumi, noshi-ba, koryu-ba, enbi-ba, rasha-ba, tsuya-ba etc. It really would be interesting to use Neos as a model organism because it has so many different characteristics that it has expressed in cultivation.