Interesting profile of Roman Catholic evolutionary biologist Francisco Ayala. As an aside they note:
In conducting the studies he had suggested, Ayala also made the unexpected discovery that the parasite P. falciparum can reproduce not just sexually, but clonally as well: it can fuse male and female gametes - sexual reproduction - or transmit all of its genes as a single unit, the cloning that was an unexpected phenomenon. Ayala's discovery has helped reveal that malaria, which now kills up to 2.7 million people per year - mostly African children - became common only within the last 5,000 years; while it once existed only in a small region of Africa, the adoption of slash-and-burn agricultural practices enabled the disease, which is transmitted by a certain type of mosquitoes, to flourish.
I suspect that the rise of agriculture and resultant population densities were one of the greatest selective forces to reshape the the genetic structure of the human species. The book 1491 chronicles the collapse of Amerindian societies in the face of Eurasian super-bugs. In North America the less numerous natives were overwhelmed by European settler colonies, while in South America a rising mestizo tide has inundated indigenous islands. Today on the Great Andaman Islands only a few dozen descents of the thousands of ancient hunter-gatherers have survived on the pathogenic onslaught unleashed by settlers from the Indian mainland. No doubt the cries of hundreds of thousands of hunters and gathers on the edge of the expanding front of cereal cultivation and the swarming folk over the past 10,000 did not merit attention because their fate was the nature of things, their gods had abandoned them. The Neolithic Revolution is often characterized as dualing paradigms of "demic diffusion" and "cultural diffusion," whole populations radiating outward on a Fisherian wave of advance, or the transmission of agricultural techniques along trade routes. But in the wake of grain and its regular bounties the horsemen of the apocalypse arrived in the train, shadows of pestilience in the wake of civilization's victory.