EEOB 3310 Exam -3 Exam With Correct Solution,2025

EEOB 3310 Exam #3 Exam With
Correct Solution,2025.




Genomes of A Population - CORRECT ANSWER✔✔In the genomes of a population of any organism, we
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known that there are many "genes" containing considerable levels of variation.
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Assume we have collected genetic data on the frequency of a trait in a random sample of the population that
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we are studying. - CORRECT ANSWER✔✔What information can we expect to have for the trait?
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-Assume the trait has Mendelian inheritance.
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-Assume we can obtain accurate phenotype frequencies.
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--Let's initially assume co-dominant inheritance (like piebald spotting in the hair of cats).
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-We can start with the phenotype frequencies and then calculate observed genotype and allele frequencies.
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Piebald Spotting in Cats - CORRECT ANSWER✔✔Co-dominantly inherited trait.
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Two alleles.
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-S=white

,-s=non-white



Three genotypes. j




-SS=>50% white j




-Ss=5-49% white j




-ss-solid non-white j




The Null Hypothesis Model for Population Genetics/The Hardy-Weinberg Model - CORRECT ANSWER✔✔
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We need to be able to make some predictions about populations. To do this logically, we need to start from a
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null hypothesis.
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What Is The Hardy-Weinberg Model?
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How Did We Get This Model? - CORRECT ANSWER✔✔Let's put our discussion into the context of science in
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the first decade of the 20th Century.
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Mendelism has been rediscovered. j j j




Biometricians are feuding with Medelians. j j j j




How important are discrete "Mendelian" traits compared to "continuous" Darwinian traits?
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Those who believed that Mendelian traits are really important presented their evidence.
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One scientist in particular: Reginald Punnett.
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"Mendelism in Relation to Disease" - CORRECT ANSWER✔✔A presentation by R. Punnett to the Royal
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Academy of Medicine (February 28, 1908).
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Emphasized the existence of simple Mendelian traits in humans. j j j j j j j j




-Some of Punnett's examples: Eye color, Brachydactyly.
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,Not So Fast - CORRECT ANSWER✔✔British statistician, in the audience for Punnett's talk--a "biometrician".
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Objected to Punnett's interpretation because of the frequency of traits in the population.
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Udny Yule (commenting on Punnett's paper): "Assuming that brown or duplex eye-colour was dominant
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over blue, if mating of persons of different eye-colours were random (and that was very nearly true), it was
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to be expected that in the population there would be three persons with brown eyes to one with blue; but
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that was not so. There were more blues than browns."
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"The same applied to the examples of brachydactyly. The author said that brachydactyly was dominant. In
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the course of time one would then expect, in the absence of counteracting factors, to get three
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brachydactylous persons to one normal, but that was not so. There must be other disturbing factors of equal
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importance."
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Yule's Comments Agreed With Others - CORRECT ANSWER✔✔Speculation by many who were skeptical of
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the importance of Mendelism:
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-For discrete traits, Mendelism predicted that gene frequencies in populations (and phenotype
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frequencies) will be pushed towards certain specific values (because of Mendelian inheritance).
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For Punnett's Human Examples, He Was Perplexed. - CORRECT ANSWER✔✔He had no answer to Yule's
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objections.
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Punnett turned to a friend, G.H. Hardy, one of Britain's most distinguished mathematicians.
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Hardy realized that Yule's objection could be answered easily (in fact, he seemed embarrassed by the
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simplicity).
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Hardy was correct, the answer was "simple." j j j j j j




Several investigators independently came up with the answer.
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, William E. Castle - CORRECT ANSWER✔✔First prominent American Mendelian.
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Dealt indirectly with the "Yule" problem in a paper published in 1903.
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Wilhelm Weinberg - CORRECT ANSWER✔✔German physician.
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Dealt directly with the problem in a paper published (in German) in January 1908.
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G.H. Hardy - CORRECT ANSWER✔✔Dealt directly with the problem in a paper published in July 1908.
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Castle-Hardy-Weinberg Model (1908) - CORRECT ANSWER✔✔W.E. Castle: j j j j j j




One of the founders of genetics in the United States.
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Professor at Harvard. j j




Wrote a paper in 1903 concerning population frequencies of alleles.
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-Special case. j




Was mentor to a number of students who were influential to American genetics.
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--Laurence H. Snyder: One of those who verified the Mendelian inheritance of the PTC "taster" trait. Used his
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OSU students, and their families, as the study group.
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Hardy-Weinberg Model (1908) - CORRECT ANSWER✔✔Simplest model for population genetics. j j j j j j j j j




-Model is based on a foundation of Mendelian inheritance.
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Assumptions:

No directive forces.
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-No mutation.
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-No selection.
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-No migration.
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