
I finished this book a week ago and can't get it out of my mind, so I think it needs a quick review.
Survival of the Sickest, by Dr. Sharon Moalem, explores and answers the question of why natural selection "failed" to weed out several hereditary diseases that are part of our genetic makeup. Moalem begins by explaining how some diseases have been passed on from generation to generation because they actually served an evolutionary purpose. These are diseases that kill us eventually, but they saved our ancestors from immediate threats, such as the bubonic plague.
Fairly interesting, right? Well, it gets even better. Many of the diseases we get actually control us for their own profit and benefit. It can be as simple as a sneeze, which helps propell the virus to find other hosts. Or more insidious, like an STD that increases sexual desire and reduces judgement. All those tropical parasites that make you itch do so for a reason.
Then it gets even more interesting. We have genetic coding that consists of innumerable "switches" that can be turned on and off based on our environment. This concept goes against everything I ever understood about genetics. For example, in one study fat yellow rats that came from a long line of fat yellow rats were given vitamin supplements in the first days of pregnancy, and they produced skinny brown rats. They still carried the fat yellow rat gene, but it was switched off because the fetus did not sense a threat to its future nutrition, so it's little body didn't need to hoard fat. Women who are on a junk food diet in the first days after conception trigger the switch that makes skinny babies, because they sense they are being born in harsh conditions and will need to be small to survive. Ironically it also triggers the switch to obesity in childhood and beyond, because they sense they will need to hoard fat later in life to survive. These traits are deeply set in our ancient DNA and helped our ancestors survive severe cold and famine. (I'm probably not explaining this accurately enough, but just giving you a taste of one aspect of the book that stuck with me.)
Aging unto death is another switch that is flipped. We are actually programmed to die. I can't do the explanation justice but it has to do with limiting rapid cell growth. In other words, aging is part of our bodies' defence agianst cancer.
So if you've ever wondered why we get sick or age, Survival of the Sickest is for you. I do not have a science background, but found this an easy and engaging read, Tipping Point- style. Five stars.
The book's website, For excerpts, reviews, etc.











































