PCB 4674 Chapter Notes -Molecular Evolution, Retrotransposon, Mitochondrion

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erinkangaroo645

22 Feb 2013

School

University of Florida

Department

Agronomy

Course

PCB 4674

Professor

Colette Marie St Mary

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Document Summary

Manx phenotype: includes both the reduced or absent tail and longer hind legs than forelegs. Usually homozygote lethality = strong natural selection against m. Founder effect: chance variation in the initial allele frequencies sin a founding population may lead to dramatically different allele frequencies on an isolated island compared to on a mainland. In experiments with small sample sizes, realized frequencies are not always very close to the expected frequencies. Modeling a hermaphroditic or monoecious species: model where male and female are placed into the same gamete pool instead of having separate pools. Genetic drift: the process of random fluctuation in allele frequencies due to sampling effects in finite populations. Genetic drift causes allele frequencies to fluctuate over time. The rate at which allele frequencies fluctuate because of drift depends on the size of the population. Selectively neutral: there is no fitness difference between the two alleles. Genetic drift is completely random, unsure which will be lost.

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.

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PCB 4674 Chapter Notes -Molecular Evolution, Retrotransposon, Mitochondrion

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