Survival of the Sickest

  
Title: Survival of the Sickest – A Medical Maverick Discovers Why We Need Disease

Author: Sharon Moalem with Jonathan Prince

Publisher: William Morrow, 2007 (First)

ISBN: 978-0-00-725886-4

Pages: 267

We know that mankind reached the stage it now occupies through a series of evolutions over eons of geological time. We also know that evolution is blind. The random mutation may tend to tip the organism in a beneficial or devastating path. If the random change is indeed beneficial, natural selection acts upon it and confers a genetic advantage to the living being by making it the creator of many offspring. Increase in progeny means more copies of genes that gave the creature the advantage in the first place. This being the prime mover of evolution, we sometimes wonder at the widespread prevalence of disease in our midst. Especially when we learn that a disease is prevalent in a particular society, we are left guessing at why evolution has not stamped out the deviant behavior after playing with it for so much time. Sharon Moalem addresses this specific issue and explains why we need disease to prevail in human societies. Citing a few examples, he maintains that those diseases might have conferred some advantage to its victims against some other menace which is equally life threatening. Patients suffering from hemochromatosis have some genetic advantage against plague; people with Type 1 diabetes perform better than others in conditions of extreme cold, quoting two examples from the book. The author discusses the mechanism of how this happens and touches upon many controversial yet interesting subjects that are at the cutting edge of biological research. Sharon Moalem has a Ph.D. in human physiology and has published several papers in immunology. He lives in New York. One note of caution is valid here though – don’t take everything the author claims in a serious note.

The reader must be prepared to receive some shocking information about quite common diseases like diabetes. A large portion of the population is forced to lead a less than satisfying lifestyle due to this malady common everywhere on the planet. Who would’ve guessed the benefits this disease had conferred on its victims in the evolutionary past? We read with astonishment that diabetes might have helped ancient people to survive in extreme cold during a sudden ice age that swept across the northern hemisphere 12000 years ago, called ‘Younger Dryas’ (being the name of an arctic flower whose pollen was found in lower latitudes during that age). A major proportion of the living population might have perished in the numbing cold. The natural advantage of diabetics in the cold is established with help from the example of an arctic frog which possess antifreeze proteins in its blood stream. These eject water from the body when cold begins and the blood become concentrated with sugar. Similar is the case with diabetics. Having a higher concentration of blood sugar, and ejecting water through frequent urination, the unforgiving ailment in the present era must have stood them in good stead by providing a survival advantage during the ice age. This caused the gene to proliferate and become quite common in the society. Moalem proposes this to be the reason behind large percentage of diabetics in Scandinavia than in tropical regions.

The author has gone full throttle in cherry-picking controversial topics for each of the book’s chapters. And nowhere it goes the whole hog than on the section on epigenetics. Here, we get an impression that Moalem had unnecessarily complicated a genuine area of earnest scientific interest by painting it in the bad light of Lamarckism. The attempts to strike at the sanctum sanctorum of evolution theory – random mutation and natural selection. Since no particular gene can be pinpointed as the cause of a perceived effect – genes being too complicated for that - evolution’s driver of random mutation which changes only one or two nucleotides is not enough to explain evolution, according to Moalem. On the other hand, he proposes the concept of ‘jumping genes’ in which a portion of the genome may be copied and pasted to another location on the DNA, and changing the phenotype that new location corresponds to. This can happen under the infection of retroviruses too. What the book tries to establish is that such wholesale genome change is to be attributed to rapid evolution. And then the issue of epigenetics is also to be thought about, which explains selective turning on and off of genes when certain methyl groups get attached to sections of the genome. In this case, the genome would be producing results totally different from a similar person, say, an identical twin. For them, the DNA is the same immediately after birth, but changes accumulate as the siblings age. The contrast is the more striking when the separation between the individuals is more. Such changes in DNA may also occur under the influence of drugs, some of which are administered to aid the child in gestation. The scenario is a scary one. The medicine you give to the expecting mother, like vitamins, folic acid and the like, has the potential to cause some deleterious effect on the children, and in rare cases, even the grand children! Ubiquitous cases of obesity in America is thought to be a side effect of certain drugs ingested by the mother during pregnancy. What Moalem wants to establish is that some characteristics acquired by the parent may be transferred to the offspring through these jumping genes or epigenetics, but the argument falls short of providing convincing evidence. When you put forward an extraordinary claim to remake the fundamentals of evolution, the proof must also be extraordinary. But the book miserably fails on this aspect and the evidence nowhere rises higher than the level of anecdotes. This unwanted tirade against a well-established concept, without satisfactory backup, has downgraded the book’s rating by a notch. If this chapter had been worded differently, the book might’ve scored a 4-star instead of the 3-star if enjoys now. But to grant justice to the author, he has warned that he is quoting from controversial research papers whenever such material was used. Probably, such liberal borrowing from bold, but controversial material has imparted good readability to the book!

The book is neat, tidy and quite easy to read. Even those of use who has only a basic exposure to biology would find it interesting, informative, easy to follow and exciting. Since man is naturally curious to know the ways a feature progresses through the progeny, chapters on genetics paves the way for engrossing reading. However, Moalem assigns undue importance to the practices followed by old custom and argues that there is strong scientific basis to it. This seems to be far fetched. People afflicted with the disease hemochromatosis may be relieved by letting out blood, but that can’t be understood to be the motive behind bloodletting as a general form of medical practice widely followed all over the world once upon a time, but discouraged now. The author’s phrase of ‘where there is smoke of custom, there is bound to be medical fire’ is crossing all limits of proportion.

Organic farming is the craze of the newly rich and overly health conscious people. The book presents an illuminating counter-argument which proves a downside of organic agriculture. Celery plants produce a toxin called psoralen, which causes changes in DNA and ill effects in humans. This psoralen is produced in copious quantities when the plant senses an attack – in the form of a worm or pest that is munching on its leaves or stem. The amount of psoralen can be up to a hundred fold in such bruised plants. When you apply synthetic pesticides, the plant is protected from physical attack. Organic farmers don’t use pesticides, and the plant is exposed to some attack, and psoralen level in the plant is increased. It all ends up with the curious result of avoiding poison outside the plant, only to end up with poison inside it.

The book is highly recommended.

Rating: 3 Star