BIOL 1111 Chapter Notes - Chapter Chapter 23: Meiosis, Dna Replication, Genotype Frequency

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mauveworm52

28 Jan 2018

School

Temple University

Department

Biology

Course

BIOL 1111

Professor

Michael Joseph Balsai

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Document Summary

Common misconception about evolution: individual organisms evolve. It is true that natural selection acts on individuals: each organism"s traits affect its survival and reproductive success compared with those of other individuals. Microevolution: as a change in allele frequencies in a population over generations. Three main mechanisms that can cause allele frequency change: Differences among individuals in the composition of their genes or other dna sequences. Some heritable phenotypic differences occur on an either or basis; ex. Mendel"s pea plants: each plant has flowers that were either purple or white. Other phenotypic differences vary in gradations along a continuum. Such variations usually results from the influence of two or more genes on a single phenotypic character. Heterozygous individual has two different alleles for a given locus. Homozygous individual has two identical alleles for that locus. Introns: non coding segments of dna lying between exons. Exons: the regions retained in mrna after rna processing.

Related Questions

The Hardy-Weinberg theorem states that the gene frequency ofpopulations does not change over time. TRUE OR FALSE?

Evolution by natural selection is a random process. TRUE ORFALSE?

In a population of 50 individuals, 20 are homozygous dominant,25 are heterozygous, and 5 are homozygous recessive. If 20% of theDOMINANT PHENOTYPE are eaten by birds, what will be the NEWRECESSIVE ALLELE FREQUENCY in the remaining population?

(Hint: How many individuals express the dominant phenotype inthe current population? In the new population?)

Question 9 options:

	A.30% (0.30)
B.	10% (0.10)
C.	36.5% (0.365)
D.	12.1% (0.121)

raspberryotter201

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

Question:

Question 1: What is NOT a force of evolution?

Mutation of genes

Genetic drift

Equilibrium of populations

Migration of populations

Question 2:

Crossing true breeding dark-coated sheep with true breedinglight-coated sheep always results in 100% dark-coated offspring.You are screening a population of 300 Soay sheep for coat color,and you count 243 dark sheep and 57 light sheep. What is thegenotype frequency of the homozygous recessive sheep forTYRP1 gene if the population is in Hardy-Weinbergequilibrium?

.421

0..176

0.864

0.190

Question 3:

In the same population, if it is under Hardy-Weinbergequilibrium, how many individuals do you expect to be heterozygousat TYRP1?

217

0.492

148

124

Question 4:

Rabbit's ears can be either short (dominant) or floppy(recessive). If a population of rabbits in Hardy-Weinbergequilibrium has 250 short eared rabbits and 100 floppy earedrabbits, what is the allele frequency of the "short" allele?

.465

0.714

0.845

0.535

Question 5:

To calculate degrees of freedom, we use the following formula:Degrees of freedom - the number of constraints imposed on yourcomparison. How many constraints are there when we use theChi-square test for Hardy Weinberg equilibrium?

Question 6:

You perform a Chi-square test for gene X and find thep-value to be greater than 0.05. What can you say with 95%certainty about this population?

This population is in Hardy-Weinberg equilibrium at theX locus: gene X isinfluenced by at least oneforce of evolution.

This population is in Hardy-Weinberg equilibrium at theX locus: gene X is notinfluenced by any forces ofevolution.

This population is not in Hardy-Weinberg equilibrium at theX locus: gene X isinfluenced by at least oneforce of evolution.

This population is not in Hardy-Weinberg equilibrium at theX locus: gene X is notinfluenced by any forces ofevolution.

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BIOL 1111 Chapter Notes - Chapter Chapter 23: Meiosis, Dna Replication, Genotype Frequency

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