Reviewed by Joe Bauman (Salt Lake City)
Marshall, M. 2020. The Genesis Quest: The Geniuses and Eccentrics on a Journey to Uncover the Origin of Life on Earth. University of Chicago Press, Chicago, IL. 368 pp. ($15.60 cloth, $10.80 paper, $10.79 e-book with 40% PS discount.)
Reviewed by Joe Bauman (Salt Lake City)
Michael Marshall, a science writer, delves into theories and experiments intended to understand life’s origins: old Norse myths, Greek philosophers, the Bible, early chemists, and into the 21st century. These include ideas such as spontaneous generation (rotting meat becomes maggots by some mysterious transformation) and the so-called “primordial soup” of chemicals, to the formation of proto-cells from oily material floating in water.
DNA, with its self-replicating double helix structure, is said to be essential in all living cells on Earth. (That may be true, but only by assuming that viruses aren't alive.) The formation of the DNA molecule was extremely complex, and the conditions that were required may preclude the popular hypotheses of thermal vents in our oceans and beneath the ice of distant moons. For one thing, Marshall notes, individual hydrothermal vents seem to remain active for only a century or so, not long enough for the many necessary chemical connections to occur.
He prefers geothermal hot ponds on land, because of their repeated wet and dry cycles. Marshall cites David W. Deamer (University of California, Santa Cruz), who has been experimenting to discover life’s beginnings. Deamer added lipids—compounds that don't mix with water—to water from hot springs in Yellowstone National Park, discovering that the lipids "rapidly assembled into vesicles," according to Marshall. Vesicles are small circular “containers” in cells that could have formed parts of protocells. Deamer found the lipids "did nothing of the sort in seawater." Deamer's team also has been able to make chains of RNA within protocells.
Another study found that living cells contain far more potassium than sodium. That is a strike against the underwater hypothesis because the ocean is full of salt (especially sodium chloride). "Instead, the evidence pointed to somewhere with more potassium than sodium, plus plenty of zinc, manganese, and phosphate," he writes, concluding that "[g]eothermal ponds ... are the only places that fit." A wet-dry cycle could develop increasingly complex chemical as the mixture is pressed together when dry, resulting in new combinations that are then exposed to other chemicals in the pond during wet periods. A sort of evolution occurs when certain non-living compounds outperform others. Additionally, solar energy would help the processes far better on land than in an ocean, the author indicates.
Overall, this is an intriguing volume for anyone wishing to know more about the possible origins of life on Earth.