Answer Happy

Dr. Nina Jablonski is an anthropologist at Penn State University, who was interested in the role of pigment change in groups of people around the world. The standard explanation for how eumelanin influences the change of skin color over time was skin cancer could develop without eumelanin and that would kill the individual. Thus, insuring only people with pigmentation in the skin would live to have offspring, and those children would be pigmented. Jablonski reckoned this was not the proper explanation for the varying skin tones, as people have typically had their children and passed on genes before the skin cancer could develop! Furthermore, if skin cancer was driving the pigmentation of human skin, everyone would have roughly the same dark skin tone. While attending a lecture, she learned about the importance of folate (a B vitamin found in green leafy vegetables) in producing normal sperm, and an uncomplicated pregnancy with subsequent normal brain development. Later work showed melanin (eumelanin and pheomelanin) protects folate circulating in the bloodstream; therefore, anyone with pigment protection will have a better chance to successfully reproduce, which puts the melanin gene (MC1R) into the next generation.
Serum falate (ng/ml) Normals (N=64) 3º Patients (N-10) Figure 2. Levels of blood folate depend on exposure to UV radiation. Subjects ("patients") were exposed to UV radiation for 9 hrs every day for 3 months, while controls ("normals") were not exposed, and their blood levels of folate were measured. 2. Fill in the blanks based on the graph above: Subjects exposed to UV radiation produced than is typical for sperm production and a successful 3. Give two reasons those individuals in higher latitudes are able to successfully reproduce, despite their skin color (hint: angle of the sunlight and temperature).