The Hardy-Weinberg Principle: Watch your Ps and Qs

The Hardy-Weinberg Principle states that allele and genotype frequencies in populations remain stable over time, given certain assumptions. What assumptions? What does the principle mean? And how do you SOLVE those Hardy-Weinberg PROBLEMS? Everything shall be revealed in this video - with some penguins of course. They make everything go down easier.

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Solution for the additional problem I showed at the end:
Allele Frequencies:
q = 0.04
p = 0.96

Genotype Frequencies:
homozygous dominant: 0.92
Heterozygous: 0.08
Homozygous recessive: 0.002

Answer to the additional problem step-by-step: http://www.penguinprof.com/uploads/8/...

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Video Details:

Population Genetics:
The Hardy-Weinberg Principle

You need to know:
gene vs. allele
gentoype vs. phenotype
understanding probabilities (and vs. or)
Punnett Square
Hardy-Weinberg Principle

Timeline of Discoveries
Darwin, Mendel, DeVries, Correns
Hardy, Weinberg, Castle

Mendelian Genetics Gets HOT
Particles are inherited!
Traits aren't blended!
Cambridge opens a department of Genetics

So What's it All About?
It's about frequencies
When talking about population genetics, we are interested in the prevalence of a particular allele or genotype in a population

The Hardy-Weinberg Principle States:
Frequencies of alleles and genotypes in a population will remain constant over time in the absence of other evolutionary influences

Assumptions
Organisms are diploid
Generations are non-overlapping
Population must be large
No immigration or emigration
No mutation in the gene of interest
No natural selection occurs (individuals reproduce at equal rates)
Mating is random

Alleles and Allele Frequency

Penguin Prof Helpful Hints
The Sum of All Possible Outcomes MUST Equal 1
p+q = 1

ALLELE FREQUENCY
2 Alleles = Genotype
p2 + 2pq + p2 = 1

What if There are Three Alleles?
(p, q and r)

Sample Problem
In a population of 1,000 penguins, 12 have blue feet. Find the frequency of the blue allele, the yellow allele and the frequencies of the three possible genotypes in this population.

Solving Hardy-Weinberg Problems
Assign the alleles
Frequency of the dominant allele is 'p'
Frequency of the recessive allele is 'q'

Calculate q by taking the square root of the number of homozygous recessive individuals

Calculate p (the allele frequencies must equal 1, so p = 1 − q)

Use p and q to calculate the other genotype frequencies:
frequency of homozygous dominant individuals = p2
frequency of heterozygous individuals = 2pq
frequency of homozygous recessives = q2

This may help:
Hardy-Weinberg Punnett Square

Try Another One...
In a population of 130,000 magical mice, green fur is dominant over orange. If there are 300 orange mice in a population of 130,000, find the following (assume population is in Hardy-Weinberg equilibrium):
1. Frequency of dominant (green) allele
2. Frequency of recessive (orange) allele
3. Frequency of each genotype