Hardy Weinberg Problems

1.In Drosophila, the allele for normal length wings is dominant over the allele for vestigial wings.In a population of 1000 individuals, 360 show the recessive phenotype.How many individuals would you expect to be homozygous dominant and heterozygous for the trait.160 individuals are homozygous dominant and 480 are heterozygous.

2.The allele for the ability to roll one’s tongue is dominant over the allele for the lack of this ability.In a population of 500 individuals, 25 percent show the recessive phenotype.How many individuals would you expect to be homozygous dominant and heterozygous for this trait?125 are homozygous dominant and 150 are heterozygous.

3.The allele for the hair pattern called widows peak is dominant over the allele for no widow’s peak.In a population of 1000 individuals, 510 show the dominant phenotype. How many individuals would you expect of each of the possible three genotypes for this trait?510 are AA,homozygous dominant, 410 are Aa heterozygous, and 80 are aa, homozygous recessive.

4.In the United States, about, 16 % of the population is Rh negative.The allele for Rh negative is recessive to the allele for the allele Rh positive.If the student population of a high school in the U.S. is 2,000, how many students would you expect for each of the three possible genotypes?720 are homozygous dominant, 960 are heterozygous, and 320 are homozygous recessive.

5.In certain African countries, 4 percent of the newborn babies have sickle cell anemia, which is a recessive trait.Out of a random population of 1,000 newborn babies, how many would you expect for each of the three possible phenotypes?640 are AA homozygous dominant, 320 are Aa, heterozygous, and 40 are aa, homozygous recessive.

6.In a certain population, the dominant phenotype of a certain trait occurs 91 percent of the time.What is the frequency of the dominant allele?The frequency of the dominant allele is .91.

Hardy Weinberg Problems

1.In Drosophila, the allele for normal length wings is dominant over the allele for vestigial wings.In a population of 1000 individuals, 360 show the recessive phenotype.How many individuals would you expect to be homozygous dominant and heterozygous for the trait.

2.The allele for the ability to roll one’s tongue is dominant over the allele for the lack of this ability.In a population of 500 individuals, 25 percent show the recessive phenotype.How many individuals would you expect to be homozygous dominant and heterozygous for this trait?

3.The allele for the hair pattern called widows peak is dominant over the allele for no widow’s peak.In a population of 1000 individuals, 510 show the dominant phenotype. How many individuals would you expect of each of the possible three genotypes for this trait?

4.In the United States, about, 16 % of the population is Rh negative.The allele for Rh negative is recessive to the allele for the allele Rh positive.If the student population of a high school in the U.S. is 2,000, how many students would you expect for each of the three possible genotypes?

5.In certain African countries, 4 percent of the newborn babies have sickle cell anemia, which is a recessive trait.Out of a random population of 1,000 newborn babies, how many would you expect for each of the three possible phenotypes?

6.In a certain population, the dominant phenotype of a certain trait occurs 91 percent of the time.What is the frequency of the dominant allele?

Introduction
G.H Hardy and W. Weinberg developed a theory that evolution could be described as a change of the frequency of alleles in an entire population.In a diploid organism that has gene a gene loci that each contain one of two alleles for a single trait t the frequency of allele A is represented by the letter p.The letter q represents the frequency of the a allele.An example is, in a population of 100 organisms, if 45% of the alleles are A then the frequency is .45.The remaining alleles would be 55% or .55.This is the allele frequency.An equation called the Hardy Weinberg equation for the allele frequencies of a population is p2+2pq+ q2= 1. P represents the A allele frequency.The letter q represents the a allele.Hardy and Weinberg also gave five conditions that would ensure the allele frequencies of a population would remain constant.

*The breeding population is large.The effect of a change in allele frequencies is reduced.
*Mating is random.Organisms show no mating preference for a particular genotype.
*There is no net mutation of the alleles.
*There is no migration or emigration of organisms.
*There is no natural selection.Every organism has an equal chance for passing on their genotypes.

If these conditions are met then no change in the frequency of alleles or genotypes will take place.

A simple class experiment will take place to serve as model of the evolutionary process in a stimulated population.This experiment is great in order to test a few of the basic parts of population genetics.In the experiment the class will place a piece of paper in their mouth to see if they can taste the chemical PTC which isphenythiocarbamide.People with the alleles AA, which is homozygous, and Aa, which is heterozygous, will be able to taste the PTC.People that can’t taste PTC are aa.


By allowing a class to see if they can taste PTC and recording the results the Hardy Weinberg equation can be usedto determine the allele frequencies of the class.

Methods
Begin by placing a piece of the PTC test paper in your mouth.Tasters will have a bitter taste in their mouth.The frequency of tasters (p2+2pq) is a found as a decimal by dividing the total number of tasters by the total number of students in the class.The frequency of nontasters (q2) is found by dividing the number of tasters by the number of people in the class.Using the Hardy Weinberg equation the frequency ofp and q can be found.q is found by taking the square root of q2.p is found by using the equation 1-q=p. Also calculate the frequencies of the North American population.Finally find 2pq that represents the percentage of the heterozygous tasters in the class.Record the results in table 8.1

Results
Table 8.1 Phenotypic Proportions of Tasters and Nontasters and Frequencies of the Determining Alleles

Phenotypes / Allele Frequencies
Tasters
P2+ 2pq / Nontasters
Q2 / p / Q
Class Population / # / % / # / %
North American Population / 55 / 45 / .33 / .67

1.What is the % of heterozygous tasters 2pq in your class? Write out the complete Hardy-Weinberg equation and show your work.

2.What % of the North American population is heterozygous for the taster trait? Write out the complete Hardy-Weinberg equation and show your work.

3. Explain the difference or similarity between class data vs. North American data