1 Name: Jessica Ogwuru Date: 1/20/2018 Period: 3rdHardy-Weinberg Practice Problems Show your work for all problems! Practice Problem to do together: 1 in 1700 US Caucasian newborns have cystic fibrosis. C for normal is dominant over c for cystic fibrosis. Instructions 1.When counting the phenotypes in a population why is cc the most significant?

2.What percent of the above population have cystic fibrosis (cc or q2)?

3.From the above numbers you should be able to calculate the expectant frequencies of all the following (assuming a Hardy-Weinberg equilibrium): ALLELE FREQUENCY CALCULATIONS: Why calculate "q" first? Because you already know q

(f)c = q = .024 Why is it now easy to find "p"? p + q = 1, so

5. Now that you know that p =.976 and q = .024. The following genotypes can be found. GENOTYPE FREQUENCY CALCULATIONS: (f)CC- Normal homozygous dominant = p2=? .9762= .953 (t)Cc -carriers of cystic fibrosis = 2pq? 2(.976) (.024) = .04686. How many of the 1700 of the population are homozygous Normal? .953 X 1700 = 1620 7. How many of the 1700 in the population are heterozygous (carrier)?.0468 X 1700 = 808. It has been found that a carrier is better able to survive diseases with severe diarrhea. What would happen to the frequency of the "c" if there was an epidemic of cholera or other type of diarrhea producing disease? Would "c" increase or decrease? Increase, since CC would die, there would be more c in the gene pool. Now… you get to practice on your own!1. If 9% of an African population is born with a severe form of sickle-cell anemia (ss), what percentage of the population will be more resistant to malaria because they are heterozygous(Ss) for the sickle-cell gene?