Essay Quiz


1			Natural selection affects allele frequencies. This happens through variations in survival and reproduction opportunities of individuals with different genomes. Allele frequencies may change rapidly when individuals acquire and die from disease. Their genetic makeup makes them more susceptible, and this will select them out of the gene pool. Which allele is responsible for sickle cell anemia, and how does it operate in a malaria environment?




2			Lactase is an enzyme produced by infants that allows for the digestion of milk sugar (lactose). Certain alleles, one stopping lactase production, the other allowing its production to persist, will together create lactose intolerance. The incidence of lactose intolerance in populations is confined to certain geographical regions, and models explaining this condition have both a genetic and cultural component. What areas of the have a high frequency of lactose intolerance? What is believed to be the original condition of our ancestors, and how did lactase persistence arise? How then did lactose intolerance arise?