I have many favorite topics which I don't blog much or at all. One of these, taken from my time in Mexico, is the history of corn. I very much enjoyed this recent article on the topic. There is this good bit:
The sequencing revealed that an astonishing 85 percent of the corn
genome is made up of "transposable elements" — short stretches of DNA,
some perhaps descended from viral invaders — that show evidence of
having moved around in corn's 10 chromosomes at some point in
evolution. Their peregrinations provided the basis for new genes, or
the on-and-off regulation of existing ones…
Corn's diversity of traits has been largely maintained, despite a
century of intensive breeding. Modern corn produces cobs that range
from the familiar farm-stand variety to lopsided baseballs and fat
pencils and have a rainbow of kernel colors. Varieties of corn can have
a greater genetic difference between them than what exists between
human beings and chimpanzees.
Walbot, the Stanford geneticist, speculates that this unusual diversity
survived because corn cultivation spread along a north-south axis. That
exposed the species to a much greater variety of environmental
conditions — temperature, day length, rainfall, altitude — than if it
had spread along an east-west axis, as did wheat.
There is extraordinary genetic information and power in corn. I am always willing to read another book on the history of corn and its breeding.