I just love this article about hybridization and the origins of different varieties of citrus fruits: “Genomics of the origin and evolution of Citrus”.
Here’s the key figure:
It’s a great example of human-induced evolution for several reasons. I imagine that most people assume that the different varieties of citrus are something like “species” in the traditional sense. People may have a vague idea that these are propagated clonally today, but may not realize the incredible complexity involved in generating the different phenotypic configurations that have become common in today’s citrus agriculture.
The real history involves wild progenitor species that have become extinct in the face of human activity, and are only visible today through their genetic traces in living farmed citrus trees. The story includes contacts between far-off human populations, and trans-oceanic dispersal of citrus species prior to the origin of humans.
It’s truly epic, and all in the pursuit of flavor.