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Survival Of The Sickest By Sharon Moalem

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Ever since life first appeared on the planet we call home, organisms have been changing in a process called evolution. Evolution favors genetic traits that helps a species thrive and reproduce and tries to weed out the traits that threaten a species’ chance of survival. Genes that give a survival or reproductive advantage spread through the gene pool faster while genes that do not help a species get less common. This key mechanism of evolution is called natural selection. But even with evolution and natural selection, genetic diseases that make people sick are still in the gene pool after hundreds of thousands of years. So why would this happen? In Dr. Sharon Moalem’s Survival of the Sickest, he proposes that many of today’s deadly genetic …show more content…

Because of this, the body absorbs iron nonstop. As a result, the body will have extremely high levels of iron, leading to fatal outcomes over time. Such consequences include “damaging the joints, the major organs, and overall body chemistry” (Moalem, p. 2). When this disease was described in 1865, it was thought that this disease was extremely rare. But it was soon discovered that this particular disease, soon called hemochromatosis, was caused by a certain gene. In the book, it states “If your ancestors are Western European, the odds are about one in three, or one in four, that you carry at least one copy of the hemochromatosis gene” (Moalem, p. 3). In other words, this is the most common hereditary disease of those of Western European descent. This brings up another question. Why would a disorder be so prevalent in the genetic pool of the Western Europeans? First, it needs to be understood that harmful bacteria feed on the iron of the macrophages to thrive. However, people with hemochromatosis have a lack of iron in their macrophages, even though it may seem like the complete opposite. Therefore, those who have hemochromatosis are less prone to infectious agents. For this reason, people with hemochromatosis were less prone to diseases like the bubonic plague and tuberculosis. During the Black Death, for people who had hemochromatosis, “though it would kill them decades later, they are much more likely. . .to survive the plague, reproduce, and pass the mutation to their children” (Moelem, p. 15). Since the mutation helped humans survive an bubonic plague epidemic in the fourteenth century, the mutation became more common in the gene pool. In order to treat this genetic disorder, bloodletting is the treatment of choice since it reduces the iron level in their body. I find it interesting that bloodletting, an

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