Assignment:
Answer each question by showing your work and circling your final answer(s). If you do not show all steps to solve each problem, you will receive 0 points, even if the final answer is correct.
1. In a species of seagull, the genes for beak length and tail color are in H-W equilibrium. How many males will you have in a population of 10,000 individuals with short beak and grey tail if the frequencies of the dominant alleles are: long beak = 0.9 and white tail = 0.2? Assume an equal sex ratio.
2. In northern Europe, a species of daffodils in Hardy-Weinberg equilibrium (generation 0) suddenly begins selling. What would be the genotype frequencies in the third generation of selling if the initial allele frequencies were: A=0.5, a=0.5?
3. What is the effective population size of a population of 2000 lions given the following parameters: 30% are males and, of these, 10% are breeding; the females are all breeding? Ne=(4)(NmNf)/(Nm+Nf)
4. Calculate the number of individuals with a dominant phenotype (assuming dominance of allele A over allele a) considering the following: the population is in Hardy-Weinberg equilibrium, it has 100 individuals, and the frequency of the homozygote recessive genotype is 0.2. (round to the nearest integer).
5. A population of deer is divided by a road. When the road has no traffic, some deer cross it and migrate from the population south of the highway to the population north of the highway. In 2013, the individuals who successfully migrated were 40, joining a population of 160 northern deer. The allele frequency for Ai in the northern population was 0.4 and in the southern population was 0.2. What is the allele frequency of Al in the northern population after migration?
6. In a population of crickets, the length of the femur is controlled by one gene (F) with two alleles Fi and F2 with Fi being dominant and producing long femurs. What are the genotype and allele frequencies if 75% of the population has short femurs and 10% is a carrier for the short femur allele?
7. What is the phenotype ratio of a cross between two heterozygote individuals at one locus? Consider one allele dominant to the other.
8. In a population of individuals the allele frequencies for Ai and A2 are 0.755 and 0.245. Calculate the expected genotype frequencies under a Hardy-Weinberg model. The observed frequencies for this population are A1A1=0.2, A1A2=0.1 and A2A2=0.7. Can you say that the observed and expected distributions are different (reject the null hypothesis) with 1% (0.01) probability of being wrong? and with 5% (0.05) probability of being wrong?
9. You are conducting a cross between two individuals. One has a dominant allele at each of two loci (AB) and the other has a recessive allele at the same two loci (ab). When you observe the frequency of the haplotypes produced, you find: 35 AB, 45 ab, 10 Ab, and 10 aB. What is the coefficient of linkage disequilibrium of the two dominant alleles?
10. After graduation, you and 19 of your closest friends (let's say 10 males and 10 females) charter a plane to go on a round-the-world tour. Unfortunately, you all crash land (safely) on a deserted island. No one finds you and you start a new population totally isolated from the rest of the world. Two of your friends carry (i.e. are heterozygous for) the recessive cystic fibrosis allele (c). 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? (apply HW even if in reality the assumptions are violated).