Genome

Media:	Paperback
Author:	Matt Ridley
Publisher:	Harper Perennial
Release date:	03 October, 2000
List price:	~~$14.00~~
Our price:	$11.20 that is 20% off!

Genome

Average rating: Stars

Genome review

The human genome is the complete set of human genes. It comes packaged in 23 separate pairs of chromosomes. Of these, 22 pairs are numbered in order of size from the largest (chromosome 1) to the smallest (chromosome 22), while the remaining pair consists of the sex chromosomes: 2 large X chromosomes in women, one X and one small Y in men. In size, the X comes between chromosomes 7 and 8, whereas the Y is the smallest. Humans have one less chromosome than apes. We are not missing one of the ape chromosomes, but rather scientists have observed our large chromosome (number 2), appears to consist of two ape chromosomes fused together.

Ridley writes 23 chapters, the first being an introduction to terms and a science primer. The following chapters are essays, taking a gene from each chromosome to tell a story relating to its function. Ridley uses clever analogies to explain complicated science. For example, he explains the genome as if it were a book:

"There are 23 chapters, called chromosomes. Each chapter contains several thousand stories, called genes. Each story is made up of paragraphs, called exons, which are interrupted by advertisements called introns. Each paragraph is made up of words, called codons. Each word is written in letters called bases...If I wrote out the human genome, one letter per millimeter, my text would be as long as the River Danube. This gigantic document...all fits inside the microscopic nucleus of a tiny cell that fits easily upon the head of a pin" (p. 7).

Ridley explains how genomes are written entirely in three letter words, using only four letters: A, C, G, and T (which stand for adenine, cytosine, guanine, and thymine). Instead of being on pages, they are written on long chains of sugar and phosphate called DNA molecules. The genome, under the right conditions, can copy itself (replication) and read itself (translation). During replication mistakes (mutations) sometimes happen. Many mutations are neither harmful nor beneficial, but a mistake in the wrong place can be fatal.

Each chapter tells of a particular gene and how it affects the individual: from intelligence and personality to disease and sexual behavior. One story tells of the search for the Huntington disease gene and the implications when it was found. In reading the defective gene scientists can actually ascertain at what age the individual will most likely begin Huntington's symptoms. Ridley writes of the implications in genetic screening and the need for thoughtful genetic counseling. He also reviews the horrors of eugenics and the implications in this exploding research frontier.

Ridley explains that most facts about individuals are products of pleiotropy, "multiple effects of multiple genes" combined with the input of the environment. This assists in making humans individuals.

A story on the "asthma gene" on chromosome 5 was included in chapter 5. Another interesting chapter was on the X and Y chromosomes. Each appears to behave in a way to protect and benefit them self which is sometimes to the detriment of the opposition (X or Y).

Because each chapter is a separate story, this book is easy to pick up and read whenever you have a short amount of time. In picking out an interesting gene from each chromosome, Ridley barely scratches the surface of the meaning of the entire human genome. Even so, what he does bring out is entertaining and thought provoking. I was left with amazement at the complexity of the human body and with the progression of science in completing this gargantuan task of genome mapping. I am most in awe at the pace of the knowledge in which we are learning about ourselves. I am sure the future will soon bring even more fascinating insights to the recipe for humans.

Genome - Matt Ridley

Genes Simpliefied

I knew of no Genes before reading this , I still dont understand them but my ignorance on this subject has come down after reading this book.

Explaining Subjects with the help of one gene in a chapter makes it interesting reading.

Matt Ridley - Genome

Ideological backlash

Had the book on my shelf for ages and when i finally took it down was prepared for an educational trip round the genome. So i had a nice thick notebook next to it and my fountain pen filled with fresh ink. My disappointment has been growing ever since.

I already started feeling a bit uneasy by the time i got to chromosome 4 and Ridley's ten page digression on the question of asthma. His conclusion on the subject is that pollution is not getting worse:

"Some modern, synthetic chemicals can cause dramatic and dangerous attacks of asthma. Transported about the countryside in tankers, used in the manufacture of plastics and leaked into the air we breathe, chemicals such as isocyanates, trimellitic anhydride and phthalic anhydride are a new form of pollution and a possible cause of asthma. When one such tanker spilled its load of isocyanate in America it turned the policeman who directed traffic around the wreck into an acute and desperate asthmatic for the remainder of his life. Yet there is a difference between acute, concentrated exposure and the normal levels encountered in everyday life. So far there is no link between low-level exposure to such chemicals and asthma. Indeed, asthma appears in communities that never encounter them. Occupational asthma can be triggered in people who work in much more low-tech, old-fashioned professions, such as grooms, coffee roasters, hairdressers or metal grinders."

So everything is just fine. But take a closer look at the (il)logic of his argument. Ridley talks about "normal levels" - but what are "normal levels"? Besides, he himself says these chemicals are a "new form of pollution". Now, either they are new or they are normal. Ridley is blatantly contradicting himself. But not only that. He talks about "old-fashioned professions". It's debatable if hairdressing is such an old-fashioned profession, but it certainly is a profession which uses loads of different, very modern chemicals in a very confined space. Besides, in what way are problems related to some "old-fashioned" production methods an excuse for newly created problems?

When Ridley reaches chromosomes X and Y, things get quite alarming. He expounds on the genetic roots of homosexuality over two pages. After delving into some Xq28 gene and then rejecting that as an explanation he reaches for another explanation: birth order. Men who have elder brothers are supposedly more likely to be homosexual. The probability increases by 33 percent for each added elder brother. Ridley makes the H-Y genes responsible. These produce a reaction in the immune system of the mother. "The effect of a strong immune reaction against these proteins from the mother would be partly to prevent the masculinisation of the brain, but not that of the genitals." In the Middle Ages, when women had many, many more pregrancies than they do today there must have been plenty more homosexuals! But another question comes to mind: why a linear increase of 33 percent? One would expect an exponential increase, indeed a point of no return, when after so and so many pregnancies the next male to be born would be bound to be homosexual.

Ridley has a philosophy, which comes out most clearly in his quote of Bill Hamilton: "There had come the realisation that the genome ... was beginning to seem more a company boardroom, a theatre for a power struggle of egoists and fractions ... My own conscious and seemingly indivisible self ... was an ambassador ordered abroad by some fragile coalition, the bearer of conflicting orders from the uneasy masters of a divided empire."

This is worse than the "war of all against all" Thomas Hobbes painted in his "Leviathan". Capitalism seems to have not only done away with any form of real cooperation between humans as a precondition for human existence, it has even done away with any form of real cooperation within our own bodies. "One of the most puzzling features of humans is their apparently unique willingness (as a species) to conform to the communal will rather than individually striking out on their own", writes Ridley in "Nature via Nurture: Genes, Experience and What Makes Us Human". Ridley's article for the Human Ecology Review Vol.1, No.1 (1993/94) is titled: "Can Selfishness Save the Environment?". Ridley says Yes, the truth staring us in the face is No.

A better book on genes is Richard Dawkins' "The Blind Watchmaker", in which he insists on the futility of explaining high levels of complexity by directly looking at much lower levels of complexity. You can't explain the workings of a combustion engine by looking at the workings of the atoms which make it up, even though without he atoms you wouldn't have a combustion engine.

Another excellent book which shades light on phony science is Stephen Jay Gould's "The Mismeasure of Man".

Consumer Bookstore