Lec 13-2 Flashcards
Hardy Weinberg Law allows us to calculate
Allelic frequency of the population
Population of organisms create a
Population of gametes
Thus
Gamete allelic frequency= Organism population allelic frequency
Hardy Weinberg Punnet square
Construct a “Punnett” square for the
gamete population (as opposed to for
individuals)
Horizontal – all the sperm alleles with
their frequency (p,q)
Vertical – all the egg alleles with their
frequency (p,q)
Then, probability of them coming
together is probability of one type of
sperm AND one type of egg
Implications of Hardy-Weinberg
Populations are not evolving because evolution results from changes to allelic frequencies
Reproduction in itself does not drive evolution (makes sense because the law states that the population is not undergoing mutation and natural selection which cause evolution)
If a population is not in Hardy-Weinberg equilibrium, one of the assumptions has been violated
Population in Hardy Weinberg Equilibrium
Have constant allelic frequencies
Non-random mating
Changes genotypic frequency
Two categories of non-random mating
Positive assortative mating
Negative assortative mating
Positive assortative mating
Like individuals prefer each other (ex tall person mates with tall person)
Negative assortative mating
Unlike individuals prefer each other
Other forms of non-random mating
In-breeding
Outcrossing
Outcrossing
Preferential mating between unrelated individuals
Evolutionary forces that can change allelic frequencies
Mutation
Migration
Genetic drift (small populations)
Natural selection
All genetic variation comes from
Mutations
At some point based on the balanced between p and q the forward and reverse mutations reach
Equilibrium
Migration is also called
Gene flow
