As a genetics PhD student in 1976, I was naturally taken with Richard Dawkins’ brilliant book The Selfish Gene, which described genes as survival machines, ruthlessly exploiting their host to propagate themselves. While I loved the book, I had a nagging feeling (as did many others) that it represented an oversimplification (not a crime for a popular science book) because it had minimised the bleedin’ obvious importance of genes having to cooperate to build their host in order to produce copies of themselves. While they do not deny that genes are selfish, Itai Yanai and Martin Lercher, biologist and bioinformatician respectively, here liken genes to members of human societies that must collaborate to ensure their survival. Using findings from the molecular revolution that only really got going in the 1980s, the authors build up a picture of networks of genes forming guilds in order to preserve their DNA dynasties.
Rather unexpectedly, the authors begin their odyssey with cancer, using this terrible disease to illustrate the idea of selfish cells that are initially generated by a series of mutations in the DNA of a normal cell, which cause it to override normal growth controls, dividing rapidly and its descendants spreading, greedily eating up the body’s resources and starving other cells and organs until the inevitable happens. Having introduced us to the concept of the mutation and the evolution of a new “species” of cells (cancer), Yanai and Lercher then take us on another evolutionary ride within an organism’s lifetime by describing the immune system. They do a great job of describing the immune system in the bacterium in very simple terms. The enemy – for example, a virus – has part of its genome incorporated into that of the bacterium, acting like a “mugshot” that the bacterium can remember next time it is attacked, a kind of Lamarckian inheritance whereby the environment (the virus) is incorporated into its genome. The authors describe the human immune system and how specialised B‑cells edit their genome to generate an enormous variety of antibody “mugshots” of pathogenic enemies that they have never seen, but might see in the future. I asked my bright (of course!) 15-year-old science-mad son if he understood that section. He didn’t. However, that’s about the only time that the authors don’t quite hit the mark. Indeed, I thought they missed a trick here by not emphasising how different cells (and their different expressed genes) within the immune system cooperate to mop up invading pathogens.
Mutation and genetic variation, particularly in sexual species where males and females mix up their genomes at every generation, allow more rapid evolution by uncovering novel combinations of genes that may have a better chance of survival. And there it is, the magic word, “combinations”. The ensuing 130 or so pages of lively text contain a panorama of examples illustrating how genes do better by combining forces in networks. Examples here include genes that work together to generate males or females, or master genes that build body structures by controlling the expression of subsidiary genes. Yanai and Lercher are masters of the metaphor, and while I felt that there were a few omissions that might have enhanced their argument, I was seriously impressed with their visions of selfish gene society, in addition to their engaging and humorous style of writing.
Charalambos P. Kyriacou is professor of behavioural genetics, University of Leicester.
The Society of Genes
By Itai Yanai and Martin Lercher
Harvard University Press, 296pp, £20.95
Published 28 January 2016