On page 21 Dr. Moalem draws us to the conclusion that the
reason Hemocromatosis was not weeded out by natural selection over time was
because although it will kill someone in the long run, in the current it will
help them survive epidemics like the Plague. This relates to Big Idea 1: The
process of evolution drives the diversity and unity of life. The reason Hemochromatosis
was selected for and has been passed down through generations is because it
protected people from the Plague and therefore allowed them to survive and
reproduce.
Hemochromatosis exists among many other genetic diseases. Is
it possible that other diseases that we recently studied in our Meiosis and
Inheritance unit (Huntingtons’s Disease, Beta Thalassemia Major, Cystic
Fibrosis, Sickle Cell Anemia, or Duchenne Muscular Dystrophy) also have
survived similarly to Hemochromatosis because of positive affects they have on
our body? As Moalem explained the Hemochromatosis originated with the Vikings,
helped Europeans survive the Black Death, and helped the Maori babies fight
infection. Research one of the diseases we recently studied and find out if it
is similar to Hemochromatosis in its evolution. Find out how it evolved and why
it still exists today. Also, try and find research that discusses what they
think will happen evolutionally to current diseases. For example, will diseases
that help us survive today but have devastating side effects, eventually change
through evolution to the point that the side effects are decreased and the
disease no longer is classified as a disease but rather a normal characteristic
of human life?
(Dana
Morgan, Dmorgan4@students.d125.org)
Moalem states that we have diseases to survive other diseases and to live till the next day. This connects to sickle cell anemia as well. Sickle cell anemia is when the body produces blood cells that are shaped like sickles or crescents instead of disks. (http://health.nytimes.com/health/guides/disease/sickle-cell-anemia/)
ReplyDeleteAs shown in the article, the disease causes pain, fatigue, shortness of breath, and more symptoms. This shows that sickle cell anemia is a disease that hurts the patient in the long run. Recently, biologists found that sickle cell anemia helped to prevent a worse disease: malaria. In the article, Mystery Solved: How Sickle Hemoglobin Protects Against Malaria, it is shown that sickle cell anemia decreases normal lifespan, but for some reason exists mostly in areas where malaria was frequent. (http://www.sciencedaily.com/releases/2011/04/110428123931.htm). This relates to big idea 1 in the way that we have evolved to obtain sickle cell anemia to prevent malaria. This natural selection of the sickle cell anemia has made it up to 1 in 10 African descendants (Campbell 278). This disease helps today in preventing malaria by "getting in the way of Plasmodium parasites infecting red blood cells, reducing the number of parasites that actually affect the host" (http://www.sciencedaily.com/releases/2011/04/110428123931.htm). This protection helps many Africans from getting infected by the mass amount of bugs that carry malaria such as mosquitoes. The current disease will remain a help to society throughout time because the effects that it creates may help all over the world against infections. The side effects that cause shorter lifespan will be more of a negative factor in natural selection in the other parts of the world that do not have a lot of malaria as it does not benefit us to survive in the environment that we live in. Therefore, it will just be a problem to the areas without malaria. Even though some diseases get cured, I don't believe sickle cell anemia will decrease in side effects as it still helps many people with malaria prevention and thus will remain a potent disease. So, sickle cell will always remain a disease, but help people prevent malaria and earlier deaths from malaria.
(Sam Lee salee4@students.d125.org)