Biology 1001A Lecture Notes - Lecture 12: Heterozygote Advantage, Genotype Frequency, Allele Frequency

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pinkserval403

27 Jan 2020

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Meanings of gene pool, genotype frequencies, allele frequencies, genetic equilibrium. Gene pool the sum of all alleles at all gene loci in all the individuals of a population. Genotype frequencies the percentages of individuals possessing each genotype. Allele frequencies the relative abundances of different alleles. Genetic equilibrium the point at which neither allele frequencies or genotype frequencies change. How to calculate allele frequencies, given observed genotype frequencies. Determine the total number of alleles by multiplying the total number of individuals by the number of alleles. Find how many of each allele are contributed by each individual and multiply this by the number of individuals of each genotype to determine how many of each allele are present in total. Homozygote individual = 2 dominant or 2 recessive alleles. Heterozygote individual = 1 dominant allele, 1 recessive allele. Divide the number of each allele by the total number of alleles to find the allele frequency.

Related Questions

Q1. What are alleles?Different forms of the same gene.Different genes.The different characteristics of an organism.Genes found only in humans.Q2. If you add up the frequency of homozygotes + the frequency of heterozygotes for one gene (i.e. at one locus) in a population, what number do you get?Q3. People who are heterozygous for the sickle-cell allele:Are susceptible to malaria but not sickle-cell anemia.Are susceptible to sickle-cell anemia but not malaria.Are not susceptible to either sickle-cell anemia or malaria.Are susceptible to both sickle-cecell anemia and malaria.Q4. In the case study in this lab, which genotype is represented by "2pq" in the Hardy-Weinberg equation?Homozygous HbAHomozygous HbSHeterozygous HbA/HbSNo specific genotypeQ5. Suppose that, in an isolated village, the proportion of individuals that have sickle-cell anemia is 0.1 (or 1 of every 10 people). What proportion of the population should be sickle-cell carriers, according to Hardy-Weinberg expectations?Q6. When you simulated the elimination of malaria at the beginning of the lab, once the allele frequencies stabilized, what was the frequency of the HbA allele?Q7. When you investigated regional differences, what was the frequency (over many generations) of the HbS allele in the village in the "slightly wet" part of Africa?Q8. What is the number of deaths due to sickle-cell anemia in a region without mosquitoes expected to be?Very lowVery highModerateRelated to the frequency of malaria allelesQ9. As long as there are multiple alleles of a gene in a population, why will the frequencies of the alleles always change over time?Because natural selection changes all allele frequencies in populations over time.Because genetic drift causes random fluctuations of allele frequencies in populations.Because diseases will eliminate some of the alleles, generating fluctuations in their frequencies.Because allele frequencies fluctuate before the alleles eventually become fixed.Q10. Imagine a huge population with a gene that has ten functionally equivalent, neutral alleles. A small but genetically representative group of individuals from the big population is transported to an island, forming a small population. Which of the statements below best describes what will likely happen over time, and why?Because natural selection doesn't act on neutral alleles, the frequencies in the two populations should remain the same over time.Genetic drift will cause one allele to first become fixed in the island population, and later to become fixed in the original, large population.Genetic drift will result in the allele frequencies of the two populations diverging over time, with alleles being lost sooner in the island population.The allele frequencies of the two populations will change similarly due to a combination of genetic drift natural selection.

indigosnake469

Hemoglobin and Fitness Instructions Directions: Neutral Evolution

1. Obtain 20 beans of two different colors (e.g., white and red). Count out 16 white and 4 red beans. The white beans represent the Hn allele and the red beans represent the Hs allele. This is the genetic makeup of your starting population. (Note: You can use any objects that can readily be categorized into two groups, such as coins, colored rocks, or paper clips.)

2.Calculate the frequency of both alleles [f(Hn) and f(Hs)] and record them in Table 1. In our experiment frequency is a measure of how many copies of a given allele exist in the gene pool (i.e., a proportion). Use decimal values. â¨

3.Arrange the beans into pairs. These pairs represent the genotype of each of 10 individuals in the population. Record the number of individuals with each genotype [f(Hn Hn), f(Hn Hs), and f(HsHs)] in Table 1. â¨

4.Now imagine that the individuals are living and reproducing with each individual reproducing at the same rate (i.e., all individuals produce two copies of each of their alleles into the next generation). Obtain enough beans to represent the next generationâ the offspring generationâand then let the parental generation âdieâ. â¨

5.Calculate the frequency of each allele in the offspring generation and record it in Table 1. â¨

Answer the questions that follow in Table 1. â¨

Table 1

	f(HnHn)	f(HnHs)	f(HsHs)	f(Hn)	f(Hs)
oiginal generation
offspring generation

Answer the following questions to help you understand the exercise:

What happened to the frequency of the common allele? â¨

What happened to the frequency of the rare allele? â¨

What happened to the frequency of the common and rare alleles when the starting frequencies were different from yours

What happens to allele frequencies from one generation to the next if there are no evolutionary forces acting on the population? â¨

greyotter669

Problem A: Shipwreck Founder Effect Genetics

In the year 1782, a small passenger schooner (the HMS Leaky) was blown off course, crashing into the rocks of a then-uncharted mid-Atlantic island. The 30 survivors built shelter and found plentiful food on the island. Within a year, it was clear that there was little chance of rescue and no means of leaving. Soon, the warm tropical nights led couples to succumb to the romantic tendencies that moonlight walks on the beach can induce. Before long, babies were born, and the ânewâ civilization of the island now known as Gilligania was off to the races.

A genetic analysis of the remains of those original islanders showed the following ABO blood type phenotypes:

Blood Type	Number of People
A*	9
B**	7
AB	4
O	10

*Four heterozygotes (iA iO) and five homozygotes for iA
** Five heterozygotes (iB iO) and two homozygotes for iB

Keep in mind that the blood type alleles iA and iB are codominant over each other, and that the iO allele is recessive to both iA and iB. If you need to do so, review the genetics of this system in Campbellâs Biology. Based on this information, please answer the following questions (show your work):

1. What were the frequencies of the three alleles in the original survivor population on the island?

2. Determine the genetic structure (allele and genotype/phenotype frequencies) for this gene system in the island population in 1932, when the island was ârediscoveredâ by cartographers. The population at that time had grown to 185 people.

THis was all the information we were given

greyotter602

Biology 1001A Lecture Notes - Lecture 12: Heterozygote Advantage, Genotype Frequency, Allele Frequency

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