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Published byEdmund Ramsey Modified over 8 years ago
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GENETIC EVOLUTION
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Gene Pool All genetic information from a population of a specific species
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Relative Frequency The number of times an allele occurs in gene pool, compared to other alleles in same gene pool
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Relative Frequency The number of times an allele occurs in gene pool, compared to other alleles in same gene pool What is the frequency Of black fur?
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Relative Frequency The number of times an allele occurs in gene pool, compared to other alleles in same gene pool What is the frequency Of black fur? - 20/50
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Relative Frequency The number of times an allele occurs in gene pool, compared to other alleles in same gene pool What is the frequency Of black fur? - 20/50 - 2/5
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Single-gene Trait A single-gene trait is controlled by one gene that has two alleles. Variation in this gene leads to only two possible phenotypes Example: Aa, Tt, SS, nn, MM, Jj
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Single-gene Trait A single-gene trait is controlled by one gene that has two alleles. Variation in this gene leads to only two possible phenotypes Example: Aa, Tt, SS, nn, MM, Jj In other words: You have It or you don’t have it
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Polygenic Traits One polygenetic trait can have many possible genotypes and phenotypes Example: Height, Skin color, eye color
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Polygenic Traits One polygenetic trait can have many possible genotypes and phenotypes Example: Height, Skin color, eye color
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In the real world Two variables control traits: - Frequency of alleles (Quantity) - Dominant or recessive
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Directional Selection Over time, an extreme phenotype is favored over other phenotypes. This causes the curve to shift.
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Stabilizing Selection Over time, phenotypes in the center are favored over others
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Disruptive Selection Phenotypes at the upper and lower end of curve are favored over the middle
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Founder Effect Allele frequencies change as a result of the migration of small populations.
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Founder Effect Example: The Amish
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Hardy-Weinberg Principle States that allele frequencies in a population will remain constant unless one or more factors cause it to change. Hardy-Weinberg Equation
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Hardy-Weinberg Principle P= Frequency of Dominant Alleles q= Frequency of Recessive Alleles P + q =1
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Hardy-Weinberg Principle P= Frequency of Dominant Alleles q= Frequency of Recessive Alleles
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