All posts by davide198

Survival of the Sickest Part 4

What did you think about the reading?

Wow! This book has been such a great read for me. The last two chapters were a good read and contained much information. Chapter 7 introduced me to epigenetics and the ape theory in chapter 8 was interesting. All the way from the first chapter to these last chapters, Survival of the Sickest has captivated my interest and picked my curiosity. I believe I enjoyed this book so much because Dr. Moalem’s perspective on topics such as diseases is different from the usual view point of many others. I’m a little upset about finishing the book, because I truly enjoyed reading this book. Hopefully, I will be able to read future books or articles by Dr. Moalem.

What did you learn?

Chapter 7 begins by talking about obesity in kids. I learned that 1/3 of American children are overweight or obese. Then, the chapter continues by introducing the main point, epigenetics. The experiment about the fat yellow mice giving birth to a thin brown mouse was remarkable because they were given vitamins and better prenatal care. They found that through DNA methylation, the mouse gained benefits like being thin and brown. Then Dr. Moalem explained how some animals have adapted to produce offspring that seem to be best fit for an environment on variables such as amount of predators. For example, a specific type of lizard is born long tail and large body or small tail and small body depending on whether or not the mother smelled a snake while pregnant. The thrifty phenotype hypothesis, states that fetuses that experience poor nutrition develop “thrifty” metabolisms that are much more efficient at hoarding energy. The trait changes but the DNA does not. Animal studies have shown that epigenetic trigger points start very early in the in pregnancy. Much research is still being done to explore further into how epigenetics affect humans. Also, some scientists have begun to see the dad’s influence in addition to the mothers. An interesting fact I learned was that offspring have a higher chance of developing asthma if their grandmother smoked rather than their mother Scientists are also finding some evidence that supports the idea that methylation of specific genes is tightly connected to cancer.

Chapter 8 begins by introducing the disease progeria. Progeria is a disease that causes a human to age extremely fast and only occurs in 1 out of 4 to 8 million births. Dr. Moalem states that because the progeria gene exists, it demonstrates that there could be genetic controls for aging. Telomeres protect the valuable DNA when cells reproduce. The chapter continues by explaining how cancer cells are able to produce telomeres rapidly, meaning there is less of a loss of genetic information. Also, stem cells are an exception to the Hayflick limit. I also learned that with a shorter life expectancy, an organism evolves faster. Then, Dr. Moalem goes on to talk about the savanna theory and the water ape theory. The savanna theory states that our apelike ancestors abandoned the forests and moved to the savanna where life was tougher, causing them to go out and find ways to capture food. The aquatic ape theory explained that our evolution comes from our ancestors much time in the water or near it.

Do you have any questions?

These last two chapters were a great read. They left me with pondering over many topics that they touched. Would it be possible to give vitamins that would alter gene expression in a child to a pregnant mother? Are there any other ways, besides smoking while pregnant, that a grandmother may have influenced their grandchildren’s genes? Like the lizard or flea Daphnia, how much can a human mother’s environment affect a child’s genes, if at all? Could a disease exist in the future that acts in the opposite way of progeria? Which theory do you think makes more sense: the savanna theory or the water ape theory?