Most of us probably think of evolution in terms of the ancient past when ape-like creatures were morphing into human form or earlier when one-celled animals were gradually changing into the next higher forms of animals, or even when dinosaurs evolved into birds. Some have likely included the domestication of plants and animals as an agricultural arm of evolution, and may have considered the mutating of a retrovirus like HIV/AIDS to be an aspect of evolution.
 

But if you read Survival of the Sickest, you will likely come away with a very different appreciation of the wonders of evolution. Dr. Moalem takes us on a journey of discovery, a journey that started in his young life as a search for a cause for his grandfather’s, and his own, as it turned out, disease of hemochromatosis (dangerous levels of iron in the blood and organs). This quest led to an answer and more questions—many, many more questions—about the true nature of the physical influences in our lives—and why we need diseaase.     
 

Dr. Moalem often writes with tongue firmly in cheek as he makes his points with vigor. Survival of the Sickest tells, if not a different story of life, then certainly one that has an uncommon emphasis. He says, “… life is in a constant state of creation. Evolution isn’t over—it’s all around you, changing as we go.  … nothing in our world exists in isolation. We—meaning humans and animals and plants and microbes and everything else—are all evolving together and our relationship with disease is often much more complex than we may have previously realized.”
 

“So to be crystal clear: everything out there is influencing the evolution of everything else. The bacteria and viruses and parasites that cause disease in us have affected our evolution as we have adapted in ways to cope with their effects. They have evolved in turn, and keep on doing so. All kinds of environmental factors have affected our evolution, from shifting weather patterns to changing food supplies—even dietary preferences that were largely cultural.”
 

Dr. Moalem puts this all into perspective with this poetic summation: “It’s as if the whole world is engaged in an intricate, multilevel dance, where we’re all partners, sometimes leading, sometimes following, but always affecting one another’s movements—a global, evolutionary Macarena.”
 

Much of the book concerns the genetic interaction of the DNA of bacteria and viruses with ours. “DNA is not destiny—it’s history. Your genetic code doesn’t determine your life. Sure, it shapes it—but exactly how it shapes it will be dramatically different, depending on your parents, your environment, and your choices.”
 

As an illustration of the dynamic nature of the science of evolution, he goes well beyond established DNA understanding with a discussion of the possibility that Lamarkian theory (individual behaviors can result in genetic modification in an individual and that trait be passed on to offspring) could be coming back in vogue.
 

There is a lengthy discussion of what the young science of epigenetics is discovering about the effects that “methylation” has on our genome. It seems that methylation is some communication media that attaches to particular genes within an individual and modifies the on/off switch and even the strength of its expression without actually modifying the DNA.
 

I found rather fascinating the claim that the behaviors of a prospective mother can alter the expression of genes in her baby, but she can influence development even before her fertilized egg has implanted in her uterus. Even more amazing, and, I think, not fully substantiated in the book, is the claim that behaviors of the baby’s grandmothers, and even of its father and grandfathers can influence gene expression in the developing fetus. He does admit, however, that the jury is still out on some of this research.
 

I loved this existential summary: “Your genes are the evolutionary legacy of every organism that came before you, beginning with your parents and winding all the way back to the very beginning. Somewhere in your genetic code is the tale of every plague, every predator, every parasite and every planetary upheaval your ancestors managed to survive. And every mutation, every change, that helped them better adapt to their circumstances is written there.”      
 

Survival of the Sickest is a fun read. I found myself smiling at the author’s use of metaphor and expression, and at a few puns he sprinkled here and there. You’ll get a different perspective on the utter pervasiveness of evolution, on how the earth operates at the biologic level, and of how we fit within it. I highly recommend it. Four and a half stars.
 

© 2007 R. Leland Waldrip