01:119:115 Lecture Notes - Lecture 39: Allele, Mutation, Genetic Drift

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apricotcrow522

5 Apr 2016

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Expected frequencies of phenotypes ( if you know the gene frequencies) Or calculate the gene frequencies if you know the phenotypes. For example: the frequency of a is 0. 7 and a is 0. 3. What is the formula: solve for p2 p2=0. 7x0. 7=0. 49 solve for 2pq. The hardy weinberg equation can test whether a population is evolving. For a population to remain in hardy weinberg equilibrium for a specific trait, it must satisfy five conditions. There must be: no mutations, random mating, no natural selection, a very large population, no gene flow between populations. Mutations are changes in the nucleotide sequence of dna that are heritable. Mutations cause new genes and alleles to arise. Only mutations in cells that produce gametes can be passed to offspring (why?) If silent- means that it does not alter structure or function. Important source of genetic variation: non random mating. Random mating= each individual has an equal chance of mating with any other individual.

Related Questions

11.The evolutionary force of drift changes allele frequencies more quickly in which of the following kinds of populations?

a. large populations

b. small populations

10.Larger populations generate larger numbers of mutations.

True

False

9.Overdominance can result in changes in genotype frequencies, without changes in allele frequencies.

True

False

8.Protein coding genes usually evolve faster than pseudogenes.

True

False

7.Favorable mutations are not directly induced by environmenntal conditions where they increase fitness, instead they occur by chance, and if they happen to increase fitness, their frequency will increase in a population.

True

False

6.Consider a single gene with two alleles, A and a, in a population. What is the frequency of the Aa genotypes in zygotes drawn from a gene pool where A=0.3 and a=0.7, if they are in Hardy-Weinberg proportions?

1. 0.3

2. .09

3. 0.49

4. 0.42

5. 0.7

1 A) Cystic Fibrosis is an autosomal recessive disease, 1 out of every 2500 individuals of Caucasian descent in the US have cystic fibrosis. What frequency of cystic fibrosis carriers would you expect in the Caucasian population of the US under Hardy Weinberg Equilibrium? Show your work. (1 pt)

1 B) You know that penguin tuxedo color is a classic Mendelian single-gene trait, the allele for black and white tux coloring (T) is dominant over gray and white tux coloring (t). In a population of penguins, there are 400 black and white tuxedoed penguins and 200 gray and white tuxedoed penguins.

(i) Which observed genotypic or allelic frequencies can be calculated from this scenario without assuming Hardy Weinberg Equilibrium? (1.5 pt)

(ii) In one to two sentences, explain why differences may arise between observed and expected genotype frequencies. (1 pt)

1 C) You are studying inheritance of external keratin features in a dinosaur. Analysis has found that the presence of feathers is due to codominance between the AS (scales) and AH (horns) alleles. In one generation of a population you find 78 scaled dinosaurs, 76 feathered dinosaurs, and 64 horned dinosaurs.

(i) What are the observed allele frequencies of AS and AH ? Use p for the frequency of AS and q for the frequency of AH . Show your work. (1.5 pt)

(ii) What are the observed genotypic frequencies? Show your work. (1 pt)

(iii) Given the allelic frequencies calculated above, what are the expected number of scaled, feathered, and horned dinosaurs in a population of the same size (218) under Hardy Weinberg Equilibrium? Show your work. (1.5 pt)

(iv) Use a chi-square test to examine whether the gene you are studying is under Hardy Weinberg Equilibrium in this population. Show your work. Do you accept or reject the null hypothesis? (2 pts)

II think this is a pretty basic Hardy-Weinberg Problem, I justdon;t know how to solve it yet. Thank you for your help!

Assume a population of 800 individuals with the followinggenotypes:452 AA, 296 Aa, and 52 aa. This is the 1stgeneration.

a. Calculate the frequencies for A___ and a___. Do this fromgenotype frequencies (do NOT assume Hardy Weinberg Equilibrium)

b. Use the allele frequencies from part a to calculate theexpected genotype frequencies for AA___ Aa___ and aa__

c. Based on your allele frequencies above, how many of eachgenotype would you expect if the population of 800 people were inHardy-Weinberg Equilibrium? AA____ Aa____aa____

d. Suppose that the original population (452 AA; 296 Aa; 52 aa)experienced an epidemic of an infectious disease that kills 75% ofeach homzygous class ( AA and aa). and 25% of the heterozygotes.How many of each genotype would survive?

e. The results of part e are still the first generation, butpost-epidemic survivors. What are the new allele frequencies?

f. Assume the 1st generation post-epidemic survivors materandomly, and there is no selection, no migration, no mutation, nogenetic drift. What frequency of each genotype is expected in the2nd generation?

g. If the 2nd generation contains 350 indivduals how many ofeach genotype do you expect?

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01:119:115 Lecture Notes - Lecture 39: Allele, Mutation, Genetic Drift

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