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Allele to Trait Frequency

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    So we just calculated the allelic frequencies up
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    here for the dominant recessive alleles, but what
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    about the trait itself? How frequent is the
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    trait of lactose intolerance in our population? Well,
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    about their homozygous dominant and our heterozygous condition,
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    they're going to be lactase persistent. And our homozygous
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    recessive condition is going to be lactase non-persistent. This
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    is the group that's going to be lactose intolerant.
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    So, if we calculate the frequency of lactase persistence in my
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    population, and we've got 500 plus 350 is 850 total people out
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    of 1,000. That's 0.85. Well, look at that! The frequency of the
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    dominant allele is 0.675. The frequency of the dominant trait is 0.85.
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    They're not the same. This is really
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    important, the allelic frequency and the trait frequency
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    don't have to match. Take this given
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    scenario right here. We have a population of
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    1000 people, remember that means we have
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    2000 alleles total. And when we calculate our
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    allelic frequency, we find that the dominant
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    allele for lactase persistence is prevalent at a
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    0.75 frequency. The recessive allele is prevalent at at 0.25 frequency.
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    When we look at the actual trait frequency, lactase
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    persistence comes in at 1.0, 100%. But lactatse
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    nonpersistent. The tray to lactose intolerance is 0,
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    0%. Now, if these things are true, then I want you to enter a possible number
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    of people for each genotype here. Remember, you have
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    100 people to choose from, so whatever your numbers you
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    put in these boxes, it should add up to a
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    1000. Based on the allelic and the trait frequencies that
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    you see here, I want you to enter in any
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    possible number of people that could be each genotype. Go
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    ahead, give it a try. If you get stuck, try
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    checking out the forums to see if anyone has some
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    helpful advice.
タイトル:
Allele to Trait Frequency
Video Language:
English
Team:
Udacity
プロジェクト:
BIO110 - Tales from the Genome
Duration:
02:09

English subtitles

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