THE VITAL QUESTION

An evolutionary biochemist argues that while single-cell life emerged early in Earth’s 4-billion-year history, complex life arose only some 2 billion years ago as the result of a rare, even freakish, event.

Lane (Evolutionary Biology/Univ. Coll. London; Life Ascending: The Ten Great Inventions of Evolution, 2009) is known as a writer of popular science, but this is a rigorous work that requires close reading and the ability—and willingness—to tackle and comprehend complex technical processes, such as chemiosmotic coupling and the ATP synthase. The rare event was an endosymbiosis between two single-cell prokaryotes, forming a eukaryote, a complex cell. When this happened, mitochondria formed from the cell that was captured inside the host cell and continued to live in the new organism. The acquisition of mitochondria changed everything, greatly expanding the cell’s genome and volume. Mitochondria contain genes in their DNA that differ from the genes in the cell nucleus and that mutate much faster than those in the nucleus. This high mutation rate lies behind our aging and certain congenital diseases such as cancer. Mitochondria may even have given rise to sex, which is necessary to maintain the function of genes in large genomes. To aid readers, Lane includes line drawings, diagrams, and black-and-white photographs, many with lengthy captions that also require close attention. A helpful glossary provides definitions of technical terms. The author writes with enthusiasm, generously gives credit to other scientists in his field, and freely acknowledges that some of his ideas may be wrong. Curiously, an epilogue reports that in 2010, Japanese scientists found an organism next to a hydrothermal vent in the Pacific Ocean that suggests that perhaps that rare event of 2 billion years ago recently happened once again.

Not necessarily for casual readers, but for the scientifically curious, a challenging book that presents ideas about the most intricate processes that link genes and energy.