Download Population Genetic

Population Genetic
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Hardy-Wienberg Law
Genetic drift
Inbreeding
Genetic Bottleneck
Outbreeding
Founder event
Effective population size
Gene flow
Population Genetics
• Genotype, phenotype
• locus, genotype frequency, allele
frequency
Determining the genotype for an enzyme in a fish.
IDHP (isocitrate dehydrogenase) from a grasshopper
Individuals
1
2 3 . . .
AA
aa
Aa
Genotype and Phenotype
• Genotypes  AA, aa (Homozygous), Aa (Heterozygous)
• Phenotype trait X = AA and Aa , trait Y = aa
• Alleles  A and a
• If p = proportion of allele A and if q = proportion of allele a
• Then p+q = 1
• Knowing p and q the Hardy-Wienberg Equilibrium gives the
expected frequency of the
three genotypes as:
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(p+q)2 = p2 +2pq + q2 = 1
AA = p2, aa = q2 and Aa = 2pq
Hardy-Wienberg Equilibrium
Assumptions
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Population size is very large
Random mating is occurring
No mutation is taking place
No immigration (geneflow)
No selection is occurring
Genetic drift
Inbreeding
A alleles common by descent
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Effective population size
Founder effect
Genetic bottleneck
Outbreeding depression
Gene flow