The Triple Helix: Gene, Organism, and Environment

Ok, so my review will be short. I believe this book is excelent since it accomplish to set clear why genetic determinism is wrong. Genes do not act by their own, they do so inside a cell which (at least in multicelular organisms) is just one more in millions (being that a prudent estimate to a small organism) whith whom it comunicates. Now, this is just part of the story, you still have to consider this organism lives in a specific habitat in which it develops (crucial step) and in which it feeds, moves (if it can), etc. So utimately genes are a full orchestra directed by surroundings.I highly recomend this book to anyone interested in Molecular Biology, Genetics or Developmental Biology, it is basic but esential.

This little book contains three lectures given by Lewontin at the Lezioni Italiani in Milan a few years ago. It is technical and aimed at an educated readership. Since there is not enough space here to discuss the entire book, I will concentrate on a brief discussion of the first, "Gene and Organism."In this lecture Professor Lewontin outlines the role that genes, environment and chance ("random noise") play in the development of an organism. As he phrases it on page 20: "the organism is not specified by its genes, but is a unique outcome of an ontogenetic process that is contingent on the sequence of environments in which it occurs." This means that you could take the same genetic code and have it unfurl in Hyde Park and get an organism different from one you would get having it unfurl on, say, the Boston commons. Lewontin shows how cuttings from the same plant cultured at different altitudes developed differentially, and in a manner that could not be predicted. The reason they could not be predicted is that there is a significant amount of random variation ("developmental noise") that occurs as the plant grows. Lewontin gives the further example of a multiplying bacterium on page 37. The bacterium divides in 63 minutes. In another 63 minutes the daughter cells should divide again, giving four bacteria, but actually there is some random variation in how long it takes them to divide, so that one daughter divides in say 55 minutes, the other in an hour and five minutes. And this continues so that the bacteria culture does not increase in pulses, but continuously in random increments. This difference in timing in multi-cellar organisms may result in morphological differences since a catalytic enzyme may arrive too late to, say, grow a side bristle on a fruit fly (an example that Lewontin gives). Lewontin applies this understanding to the development of our brains on page 38. First there are random connections set. "Those connections that are reinforced from external inputs during neural development are stabilized, while the others decay and disappear." This process, Lewontin advises us, can lead to differences in cognitive function that are neither strictly genetic nor strictly environmental. They are influenced by random (unpredictable) factors.This understanding is the reason that Lewontin is less than thrilled with the Human Genome Project. He believes, as he makes clear in another book, It Ain't Necessary So: The Dream of the Human Genome and Other Illusions (2000), that we will be disappointed by what can be accomplished simply from sequencing the genetic code, his point being that even though we know the code, the environmental and random factors cannot be known in any precise or predictive sense. It is true that the genome for a chimp will always code for a chimp and never for a rabbit, but whether that chimp is good at math or has unusually aggressive tendencies is something we cannot know from an understanding of the gene

This little book is a nearly perfect antidote to books like Matt Ridley's Genome which tend to overstate the importance of decoding the human genome. In this wide-ranging discussion, Lewontin argues, among other things, that genes do not 'compute' organisms, and that organisms actively 'construct' their own environments. Lewontin's writing is elegant and concise. He succeeds in communicating (sometimes difficult) concepts in ways that a layman can understand.P.S. The book information given above, as to page count, is inaccurate: I count 136 pages, not 192. Indeed, my only minor complaint is that the book is rather expensive, considering its length.

Richard Lewontin's "The Triple Helix" is a delightful literary composition in four movements consisting of three lectures and an essay on contemporary trends in biology and genetics. While the three in the triple helix metaphor refers to the interactive nature of a gene, an organism and an environment, it is also a reference to the notion that the human DNA (double helix) nucleotide-sequencing project is less than the be all and end all of genetics research. In the first movement (Gene and Organism), Lewontin reviews major discoveries in biology from Darwin to the Genome Project. In his critique the author carps the metaphors of biology, especially the once useful words and phrases like Decarte's metaphor of the world as a "machine", general use of the word "development" (unrolling or unfolding of something that is already there) to mean ontogeny and embryo genesis and the "Holy Grail", i.e., the Genome Project (the project that determined the nucleotide sequence of the entire human genome). Using elegant examples from contemporary biology, Lewontin dispenses with the ideas (1) that a cell is anything much like a machine and (2) that as a blueprint, DNA sequencing would be sufficient to define anatomy, development and function. In the second movement (Organism and Environment), the author clears up the meaning of "ecological niche". Accordingly, environment and organism are so closely related that, except in the laboratory, neither exists in the absence of the other. "Organisms not only determine what aspects of the outside world are relevant to them by peculiarities of their shape and metabolism, but they actively construct, in the literal sense of the word, a world around themselves."In movement three "Parts and Wholes, Causes and Effects"; the reader is treated to a glimpse into Lewontin's home life:"As I write this chapter I think at one moment of the sentence I am writing, but then I wonder which sonata my wife will practice next, and then I recall the work done by the plumber today and then I return my attention to the manuscript."Also included in movement three are (1) highly instructive lessons on values of fitness of nine genotypes in the Australian grasshopper (2) a discussion of variety among ceratopsian dinosaur horns and collars (3) a story about a Vermont man with a 150 year-old axe, and (4) the history of infectious disease in nineteenth century Europe.In the finale, Lewinton dispenses with holism, Gaia, catastrophe, chaos and complexity theories and adds:"Rather than searching for radically different ways of studying organisms or for new laws of nature that will be manifest in living beings, what biology needs to do to fulfill its program of understanding and manipulation is to take seriously what we already know to be true . . . the fact that biological systems occupy a different region of the space of physical relations than do simpler physico-chemical systems . . ."and "New experimental techniques are in part induced by the

Lewontin is a challenging and original thinker and this book reflects his grappling with the current trends of evolutionary biology. It is also a call to return to the "first principles" of science: experiment and observation without preordained judgments, some of which he seems to challenge as even ideologically based. The unspoken question, it seems to me, in much current biological/genetic research is the nature/nuture debate. Lewontin stakes a claim that, while this is an interesting question, the question itself my be wrong, because it incorrectly shapes a number of other questions scientists ask. The dialectic between the organism and its enviroment, captured by Lewontin using the term "coevolutionary process," is far too complex to be rendered in the reductionist terms of nature/nurture. With a spate of "evolutionary" explanations for everything, he provides a fair, well-stated and welcome warning.