Practice HardyWenberg 2017 - Practice Hardy-Weinberg 17 1 100 years ago a person started a herd of horses with a red horse(RR and a white horse(rr

# Practice HardyWenberg 2017 - Practice Hardy-Weinberg...

• 1

This preview shows page 1 out of 1 page.

Practice Hardy-Weinberg 17 1. 100 years ago, a person started a herd of horses with a red horse (RR) and a white horse (rr). All of their F1 offspring were roan (Rr). Many years later, the herd had grown to 500 horses. Assume that random breeding occurred. Of the 500 horses, how many would you expect to be red?a) What is p? homozygous dominate genotype What is q? homozygous recessive genotypeb) What value in the Hardy-Weinberg equation represents the frequency of “red horses”?C) How many horses should be red?2. After graduation, you and 19 friends build a raft, sail to a deserted island, and start a new population, totally isolated from the rest of the world population. Two of your friends carry (are heterozygous for) the recessive cystic fibrosis allele, which in homozygotes causes cystic fibrosis. Assuming that the frequency of this allele does not change as the population grows, what will be the incidence of cystic fibrosis on your island? A= normal allele; a = cystic fibrosis (autosomal recessive)a) How many people are in the beginning population? ___________. How many total alleles does this represent? __________b) How many alleles are for normal (A)? ________ How many for disease (a)? _________So, 2/40 represents which variable in the HW equation? ______________c) What is q? _____________ What is q2? _____________d) What is the frequency of people who are carriers of CF? ______________3. Albinism is a rare, genetically inherited trait that is only expressed in the phenotype of homozygous recessive individuals (aa). The most characteristic symptom is a marked deficiency in the skin and hair pigmentmelanin. This condition can occur among any human group. The average human frequency of albinism in North America is only about 1 in 20,000. About what percent of the US population must be a carrier?a) What value does the 1/20,000 represent? _____________ (1/20,000 = .00005)b) What is q? _______________ What is p? ________________c) What percent of the population is probably a carrier? _____________