BIOL201 Lecture Notes - Allele Frequency, Null Hypothesis, Population Genetics

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burgundyoyster582

11 Apr 2014

School

University of Alberta

Department

Biology (Biological Sciences)

Course

BIOL201

Professor

Michael Harrington

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Document Summary

Biology 207 - practice questions 10 - population genetics. Question 1 in a wild population of sneetches you notice that 2/3 of the sneetches have stars on their bellies and 1/3 do not. Let p = frequency of the bstar allele. Let p = frequency of the bnostar allele. Let q = frequency of the bstar allele q2 = 0. 667 q = 0. 817 p = 0. 183. Note that in both cases the recessive allele was more prevalent in the population. There is no rule that the dominant allele has to be more prevalent. Question 2 both of the populations of flowering plants i used in class were in hwe. We can determine this by calculating the frequency of the cr allele (p = 2x116 + 211 / 1000 = 0. 443) and the cw allele (q = 211 + 2x173 / 1000 = 0. 557).

Related Questions

Part A

In humans, individuals may or may not have a widowâs peak. This trait is controlled by genes at a single locus, with the allele for having a widowâs peak dominant to the allele for not having one. A population of humans is sampled; 59 have a widowâs peak and 44 do not. 25 of the people with a widowâs peak are homozygous dominant. What are the frequencies of the dominant and recessive alleles observed in this sample?

p = _____

q = _____

Part B

In a species of corn, individuals have either narrow or wide corn cobs. This trait is controlled by genes at a single locus, with the narrow cob allele dominant to the wide cob allele. A farmer counts 74 narrow cob and 113 wide cob plants in a field. Of the narrow cob plants, 28 are homozygous dominant. What are the frequencies of the dominant and recessive alleles observed in this sample?

p = _____

q = _____

Part C

In a population of peas, the frequency of the dominant allele for a purple flower is 0.61 and the frequency of the recessive allele for a white flower is 0.39. What would the genotypic frequencies be if the population is in equilibrium?

_____ = Frequency of homozygous dominant individuals

_____ = Frequency of heterozygous individuals

_____ = Frequency of homozygous recessive individuals

How many individuals would you expect of each genotype in a population of 500 peas?

_____ = Number of homozygous dominant individuals

_____ = Number of heterozygous individuals

_____ = Number of homozygous recessive individuals

Part D

In mice, a mahogany coat color allele is dominant over the tan coat color allele. In a population of mice, the frequency of the allele for mahogany coat color is 0.19 and the frequency of the allele for tan coat color is 0.81. What would the genotypic frequencies be if the population is in equilibrium?

_____ = Frequency of homozygous dominant individuals

_____ = Frequency of heterozygous individuals

_____ = Frequency of homozygous recessive individuals

How many individuals would you expect of each genotype in a population of 100 mice?

_____ = Number of homozygous dominant individuals

_____ = Number of heterozygous individuals

_____ = Number of homozygous recessive individuals

Part E

In humans, the free earlobe allele is dominant over the attached ear lobe allele. In a population of humans, the frequency of the allele for free earlobes is 0.42 and the frequency of the allele for attached earlobes is 0.58. What would the genotypic frequencies be if the population is in equilibrium?

_____ = Frequency of homozygous dominant individuals

_____ = Frequency of heterozygous individuals

_____ = Frequency of homozygous recessive individuals

How many individuals would you expect of each genotype in a population of 25 humans?

_____ = Number of homozygous dominant individuals

_____ = Number of heterozygous individuals

_____ = Number of homozygous recessive individuals

rubyleopard160

I'm sorry for putting two questions on one request but I'mrunning out of uses for my subscription period. Please help!

1. Answer the following questions

(a âd) given the following information.

Please show your mathematical equations used and your work forfull credit, highlight your final answer:

Suppose we have one locus with two alleles with the followingabsolute viabilities

and initial allele frequencies.

Absolute viability:

AA = 0.95

AB = 0.95

BB = 0.65

Initial allele frequency:

Frequency A (p) = 0.2

Frequency of B (q) = 0.8

a. What are the relative fitnesses of the genotypes?

b. What is the average fitness in the population?

c. Assuming a general selection model what will the frequency ofboth alleles A and B be after one generation of selection?

d. What will the percent (%) change in the allele frequency of Abe after one generation of selection?

Will it be an increase or decrease change?

2. In wild Soay Sheep horn size is largely determined by asingle gene with two alleles. Let us assume for simplicity thatsheep with the dominant allele, H⁺, have large horns andsheep with recessive allele, H^s, have short horns. Belowis a table showing the relative reproductive success of individualswith the following genotypes. Assume relative reproductive successis our measure of relative fitness of genotypes.

Answer the following question (a-Âe).

Relative Reproductive Success:

H+H+ is 1

H+Hs is 1

HsHs is 0.60

a. What is the selection coefficient (s) value against therecessive allele (Hs)?

b. What type (mode) of selection is occurring at this locus ANDwhat is the relationship of the relative fitnesses of thegenotypes?

c. You want to model selection at this locus to determine therate at which the advantageous allele frequency will change afterselection. What is the proper equation to use to determine theallele (H+) frequency change after one generation of selection?

d. Assume before selection the initial allele frequencies areH+=0.1 and Hs=0.9. What will the change in H+ frequency be afterone generation of selection against the Hs allele? Show yourmathematical work and highlight your final answer.

e. Draw a predicted graph of the rate of change for H+AND Hs over say 600 generations. I am interested in if you can (a)label your axes correctly, (b) indicate the initial allelefrequencies correctly, and (c) show the predicted trendlines for the change in allele frequencies over generations.You should make one graph with two lines (one for H+ and one forHs). Label your lines as H+ and Hs, This eans you do notneed to perform any math to make your plots.)

burgundyyellowjacket390

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)

BIOL201 Lecture Notes - Allele Frequency, Null Hypothesis, Population Genetics

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