Question

1. In a population of mice a particular locus has two alleles A₁ (dominant) and A₂ (recessive). There are 126 A₁A₁, 167 A₁A₂ and 88 A₂A₂. Is this population in Hardy-Weinberg equilibrium (3 pts)?
   
2. In a population of Gragons, there are 3151 A1A1, 1678 A1A2 and 2014 A2A2 individuals. If the environment changes so that the homozygous recessive genotype suffers a reduction of fitness where its fitness is now 0.73, but the other genotypes are unaffected, what will be the frequency of each allele in the next generation (3 pts)?
3. In a population of Bowsers, there are 2134 A1A1, 1432 A2A2, and 1678 A1A2 individuals. If the fitness of the individuals with the recessive phenotype is 0.81, what do you predict will happen to the recessive allele over many generations and why do you think that. You must show the work you used to reach your answer and explain why the numbers support your answer (3 pts)
4. If you are studying a homozygous recessive human disease where the recessive allele frequency is 0.03. Individuals with this disease has a fitness of 0.72. You find that the allele frequency for this allele doesn’t appear to be changing, but that there is no identified selective benefit to this allele. You propose that the trait is in mutation-selection balance. Show the calculations you need to do to see if this is the case. Based on your results, is it likely that this trait is in mutation-selection balance? Why or why not (4 pts)?
5. A small island contains a population of babbits at Hardy-Weinberg equilibrium with three phenotypes (Black (BB), Grey (Bb), and Yellow (bb)). This population has 83 Black, 250 Grey, and 216 Yellow babbits. If 20 individuals migrate in from another population with q = 0.12, what will the new values of p and q be for the babbits on the island? (3 pt)
6. You are farmer, trying to breed a new strain of crops that are resistant to a new kind of fungal infection. This fungal infection kills all the crop plants it infects and none of them survive to reproduce. The new strain you have developed seems to have very slight resistance, and you are trying to use breeding experiments to increase the resistance. Your breed the most resistant strains with one another and in the next generation, you find that there was a 3% increase in the plants resistance to the fungus. What is the narrow-sense heritability of this trait, what does it suggest for how quickly you will be able to breed crops that have high resistance to this fungus, and why do you conclude that (3 pts)?
7. You are studying a population of snakes living on an island in Lake Erie. The snakes on the island all tend to be a uniform brown color (with either the BB or Bb genotype). Individuals that allows them to be camouflaged in the sand on the island. Snakes of the same species on the mainland tend to have dark stripes due to bb genotype. Striped snakes do poorly on the island because they are not camouflaged. However, you will typically find some striped snakes on the islands even though they are not able to cross the water and they are not being transferred by people. You survey the islands and find 499 BB, 305 Bb and 38 bb. The bb individuals have fitness of 0.5, while the others are unaffected by selection. Assuming that the striped snakes are being produced by mutation with a standard mutation rate of 1 in 50,000 (and that the mutation rate from b à B can be ignored), what will be the value of p and q on the island in the next generation (3 pts)?

	# of individuals with each genotype
Population	+ / +	+ / –	– / –
1	94	69	18
2	112	73	21
3	67	4	2
4	92	23	9

You are working in a laboratory that is studying the characteristics of a gene that is associated with a newly described disease. The dominant form of the gene (represented by a + in the table below) does not cause any disease, while the recessive (represented by – in the table below) does cause the disease. Heterozygotes are also unaffected. You examine several populations and gather the information in the table below. Now imagine that you are examining a second disease, but that the recessive form of the gene provides some protection against this second disease (through heterozygote advantage, perhaps). As a result, the fitness values are w₁₁ = 0.75, w₁₂ = 1 and w₂₂ = 0.82 If this is true, which one of the four populations is most likely to live in an environment where that second disease is present and what leads you to that conclusion? (4 pts)

Answer 1

1. Answer : The population in Hardy - Weinberg equilibrium

Calculation :

1. To know a population in Hardy- Weinberg equilibrium we have to prove * ① p+9 = 1 p?+ 209 + 92 = 1 where pe domenant allele 9= recessive allele =A, = A2 Frequency Frequency Geenotypic Frequency: Al Al Al A2 A2 A₂ No of individuals » 126 167 Total No of individuals = 126 +167+88 = 381 Number of alleles in gene pool → Total = 2x381 = 762 A, alleles = 2x126 +167 = 419 Az alleles - 2x88 + 1®7 = 343 Allelic Frequency= A = 44.92 = 0.549 = 0.55 A2 = 343 = 0.45 so A + A2 = 0.55+ 0.45 = 1