I see much rejection of "New World" plant foods, yet whole-hearted
acceptance of grass-fed bison, wild turkey, white-tailed deer, capybara,
etc. (which are all "New World" foods, albeit animal). In my experience.
aside from a few isolated genera and families, the only differences between
"New World" and "Old World" foods is, with few exceptions, special.
There is no scientific basis (that I have found) for rejecting whole groups
of foods simply because they normally grow on one continent or another.
Their physiological and chemical makeup is not all that different from any
other related (and cross-continental)  excepting a general uniqueness of all
individual species which allows us to categorize them as "species"; indeed,
every species and many individuals produce a unique mix of chemicals that
make that species or individual distinct.
Interestingly, Solanaceae (including tomatoes and potatos, and about 2600
other species) is not an isolated "New World" group. It is spread world-wide
in tropical and temperate regions, and is a very diverse family including
both highly toxic species, non-toxic species and many in-betweens.
Unrelated to this topic, but I did see it mentioned: "How did they figure
out how to apply caustic chemicals to change the make-up of corn (or other
food product)?"
Simple. Ashes from a fire, when soaked in water, produce potash lye. I
remember doing strange things as a child (and I still do strange things),
and I could certainly see myself experimenting with ashes and a pot of corn.
I wouldn't risk the whole lot on it, but sometimes experiments pay off. We
are a curious species, highly opportunistic, and quite diverse. Why must
there be "one right way" to go about doing something, even paleo dieting?

Ellie