"a_plutonium" schreef
I believe
the origins of potato are South America and the origins of tomato
somewhere in Africa.

***
An unfounded belief
* * *

A genomics of these two species should provide clues as to which came
first and whether
one is the ancestor of the other.

***
By definition, neither is the ancestor of the other.

Also, both are the product of a long process of breeding, that is artificial
selection. As opposed to evolution, based on natural selection.
PvR