(p. A13) Mr. Mindell, a senior researcher at UC Berkeley’s Museum of Vertebrate Zoology, offers an account of “horizontal” evolutionary processes that are not an alternative to the established view but a tweak and an addition.
. . .
The book . . . offers an updated, more sophisticated appreciation of how some living things, some of the time, exchange genes with members of the same generation.
. . .
Introgression—the mixing of genes between species—has been revealed in human ancestry by the presence, in modern populations, of Neanderthal and Denisovan DNA. Mr. Mindell points to other cases of introgression, including between coyotes and gray wolves and between brown and polar bears. “All hybridization phenomena, including introgression,” he writes, “qualify as horizontal evolution, because genetic material is exchanged between different species, rather than between parents and offspring, the path of vertical evolution. They denote networking rather than branching.”
. . . . . . inter-species hybridization still has a vertical component. A notable exception is recombination, a process that is widespread in bacteria, archaea and certain viruses. Among these populations, individuals will occasionally connect, exchange genetic material and then go their separate ways: the equivalent of a one-night stand, with important consequences for human health. It is in part because of their penchant for such networking that the viruses that cause AIDS, influenza and Covid-19 are so quick to evolve and thus so difficult to combat.
As “The Network of Life” ably demonstrates, horizontal evolution has shaped ancient processes that have set the stage for life as we know it. Mr. Mindell pays special attention to endosymbiosis, in which one tiny organism comes to reside inside another, sometimes creating a merger. “Some of the most consequential innovations in life’s 3.8-billion-year history,” he writes, “stem from a joining of previously distinct lineages by endosymbiosis.” The process gave rise to mitochondria, the “energy powerhouses” of our cells, and to chloroplasts, the intracellular denizens that enable plants to conduct photosynthesis.
For the full review see:
David P. Barash. “BOOKSHELF; Natural Mixer.” The Wall Street Journal (Friday, June 28, 2024): A13.
(Note: ellipses added.)
(Note: the online version of the review has the date June 27, 2024, and has the title “BOOKSHELF; ‘The Network of Life’ Review: Natural Mixer.”)
The book under review is:
Mindell, David P. The Network of Life: A New View of Evolution. Princeton, NJ: Princeton University Press, 2024.