Survival of the Sickest (book)
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| Survival of The Sickest : A Medical Maverick Discovers Why We Need Disease | |
| Author | Dr.Sharon Moalem with Jonathan Prince |
|---|---|
| Country | USA |
| Language | English |
| Subject(s) | Evolution |
| Genre(s) | Non-fiction |
| Publisher | HarperCollins Publishers |
| Publication date | 2007 |
| Media type | Print (Hardback) |
| Pages | 267 p. |
| ISBN | ISBN 978-0-06-088965-4 |
Survival of the Sickest is a 2007 New York Times bestseller about evolutionary biology by Dr. Sharon Moalem with Jonathan Prince in which he explains why we have deadly genetic diseases. He argues that some of those "bad genes" which cause diabetes for example, helped our ancestors survive at some point in our evolutionary history. Knowing the environment where those genes were beneficial to our survival, may help to deal with the disease.
Based on a new field called epigenetics, new research has discovered that there may be some truth in the previously debunked Lamarck's theory that proposed traits acquired in the lifetime of a parent(s) could be passed on to its offspring which can in turn be passed on through succeeding generations.
Continually, the static evaluation theory wherein gene mutations are attributed to random occurrences is also changing. Evolution is highly subject to circumstantial factors. New research shows that gene mutations can also be triggered by other genes called the jumping genes. These mutations are caused by environmental pressures, and are not random. They are believed to most likely benefit the organism, in that particular environment change. If these environmental pressures occur during early pregnancy, these mutations, "traits" can genetically be passed on to child. Problems may occur if the environmental pressure is only temporary.
Can diabetes which develops later in life, be caused by a false environmental pressure during or before pregnancy? These are the questions which Dr. Sharon Moalem tackles in his book, Survival of the Sickest.
Contents |
[edit] Summary
Hemochromatosis: The book starts with a description of an inherited disease called Hemochromatosis, where the body absorbed too much iron into the blood stream. The iron build up can cause serious problems. So why do we have this disease? Going back in history, when was an environment pressure to fever the gene of Hemochromatosis? We need to go back in time where plagues were commonplace, where quarter or more of the population died.
Infection can feed on iron, so our body has an iron-locking mechanism at place of infection. People with normal iron level were more vulnerable to the plague, as the infection can feed on them. However people with Hemochromatosis, with higher than normal iron level, their iron-locking response were superb and were going on all the time as a permanent condition. So Hemochromatosis may kill its patient at an older age, but he or she more likely survive a plague.
Diabetes: The book continues with the description of the different type of diabetes including gestational diabetes. The disease partially genetic, and because it more likely to occur in certain population, it probably helped our ancestors survive somewhere in our evolutionary line. Type 1 Diabetes is more common in the north, and much less common in people from Africa, and Asia.
Climate change and ice ages are described in details, then there is fascinating description of what kind of mechanisms that may have been selected through natural selection to help our ancestors and other plants and animals survive the cold. ... Why we need to pee, when we are exposed to cold for a while? Did you noticed when you go to swim in a cold lake during summer, and you need to pee. Why? ... How the wood frog freezes solid? ... When its getting cold the enemy is water, the body has to get rid of it or turn it to an antifreeze. Sugar is a natural antifreeze. So diabetes may helped our ancestors survive the ice age, when it was cold and food in limited supply.
At the end of the book, Dr. Sharon Moalem speculates that diabetes may be turned on during pregnancy if the environment conditions indicate that the new born will be born in a cold and food limited world. This traits developed based on the theory that in the past rapid climate change occurred, so the capability of turning on and off the diabetes gene give our ancestors a survival advantage.
Cholesterol: "Cholesterol is required to make and maintain cell membranes. It helps the brain to send messages and immune system to protect us against cancer and other diseases. It's a key building block in the production of estrogen and testosterone and other hormones. And it is essential component in our manufacture of vitamin D through a chemical process that is similar to photosynthesis in its dependence on the sun. ... our skin converts cholesterol to vitamin D."
We need a certain amount of sunshine on our skin, not too much, not too little. Our skin color regulates that. If you would migrate from South to North or viser verser, your skin color would change probably in a century. That's why you may be genetically closer to a different color person than to a same color one living elsewhere.
Toxic plants: "From an evolutionary perspective, it's not surprising that plants have evolved mechanisms to ensure that their predators think twice before making them their next meal. What's more surprising is why we continue to cultivate and consume thousands of plants that are toxic to us. The average human eats somewhere between 5,000 and 10,000 natural toxins every year. Researchers estimate that nearly 20 percent of cancer-related deaths are caused by natural ingredients in our diet. So if many plants we cultivate are toxic, why didn't we evolve mechanisms to manage those toxins or just stop cultivate them? Well, we have. Sort of. ...
Host manipulation: The book contains lot of interesting examples where the parasite, chemically change its host to behave the parasite advantage.
Epigenetics: "... Somehow, an expectant mother's mental state can trigger physiological or epigenetic events that can affect her pregnancy and the relative viability of male or female fetuses. Good times mean more boys. Tough times mean more girls. And epigenetics means we've got more - much more - to learn."
It is like our genes is a kind of information storage like a library, containing all the information, much much more than we use. Epigenetics decides what information to apply to the individual from the library. Bad behavior, like smoking or environment pressure can trigger epigenetic changes, and the bad, "punishing" genes may be turned on, and so different information is applied from the library.
So our gene manifestations are not static, can be turned on and off during a person live time. And some of that can be inherited by our child.
Aging and Cancer: We and all our cells are programmed to die, except some rebellion cells, those are the cancer cells; they want to live for ever.
There are a whole arsenal of weapons our body is using against cancer.
Water Birth: The old hypothesis that our ancestors started walking on two legs in the savanna is changing. It is very likely that our human like ancestors lived in or near water. Standing in two legs we were able to go into deeper waters. The new hypothesis that we lived near water, explains many things, like why we do not have hair in our bodies, why we have fat under our skin, and why babies can instinctively swim after birth. ... And may be that's why evolution let giving birth be painful and dangerous; it meant to happen in water. Research does show that giving birth in water seems to be easier, and less painful especially for a first birth.
[edit] Criticism
Survival of the Sickest has generally received positive reviews in mainstream media. On the website Amazon.com it has garnered a rating of 4.5 stars. Among science bloggers however, the book has met with criticism for its support of controversial ideas.
