Download HARDY-WEINBERG and GENETIC EQUILIBRIUM

HARDYWEINBERG
AND GENETIC
EQUILIBRIUM
CH. 16-1 PP 317-320
THE GENE POOL
• Population – group of the same
species living in the same area.
THE GENE POOL
• In a population, organisms tend to
show small variations of a trait
• EX: __________________
THE GENE POOL
• In a population, organisms tend to
show small variations of a trait
• EX: __________________
• Gene Pool- total genetic information
stored in a population
• EX: __________________
THE GENE POOL
• In a population, organisms tend to
show small variations of a trait
• EX: __________________
• Gene Pool- total genetic information
stored in a population
• EX: __________________
• Allele frequency- Each allele exists at
a certain frequency
• EX: __________________
VARIATION OF TRAITS
IN A POPULATION
• Histogram- graph showing frequencies of
each trait. Usually displays a bell curve.
VARIATION OF TRAITS
IN A POPULATION
• Histogram- graph showing frequencies of
each trait. Usually displays a bell curve.
• Bell Curve – shows that most members
of a population have a similar variation
of a trait. Only a few individuals display
extreme variations of the trait.
EX: A few fish are
very short and a few
are very long, most
are of average length
WHAT CAUSES THESE
VARIATIONS?
1. Mutations- Random change in DNA passed to
offspring
WHAT CAUSES THESE
VARIATIONS?
1. Mutations- Random change in DNA passed to
offspring
2. Recombination- reshuffling of genes during
Meiosis
a) Independent assortment
b) crossing over
VARIATION OF TRAITS
IN A POPULATION
1. Mutations- Random change in DNA passed to
offspring
2. Recombination- reshuffling of genes during
Meiosis
a) Independent assortment
b) crossing over
3. Random pairing of gametes
HARDY-WEINBERG GENETIC
EQUILIBRIUM
Hardy-Weinberg equilibrium describes
populations that are not evolving
Genotype frequencies stay the same over
time as long as certain conditions are met:
• Very large populations
• No emigration or immigration
• No mutations
• Random mating
• No natural selection