lecture 12 Flashcards
population
localised group of individuals of the same species
gene pool
total aggregate of genes (and their alleles) in the population at one time
motivation for Hardy-Weinberg thereom
allele frequencies remain constant over time unless acted upon by evolutionary forces
assumptions of the Hardy-Weinberg Theorem
large population size random mating no migration no mutation no natural selection
allele frequency equation 1
p + q = 1
genotypic frequency 2 alleles equation 2
p^2 + 2pq + q^2 = 1
genotypic frequency 3 alleles
p^2 + 2pq + q^2 + 2pr + 2qr + r^2
Ways in which allele frequencies change
types of mating random genetic drift bottleneck effect founder effect natural selection gene flow/migration mutation
random genetic drift
a random change in allele frequencies due to sampling error over generations
bottleneck effect
big population reduction and diversity with altered allele frequencies
founder effect
only a few individuals establish a new population with less genetic diversity
types of selection
stabilising, directional, disruptive
sexual selection
attracting a mate
frequency dependent selection
every year phenotypes fluctuate
cline
gradual change in phenotypes geographic distribution of genetic variation
mutation
very slow and usually disadvantageous
migration
individual from another population successfully mates to gene pool
