7.2 population genetics

Population

A group of organisms belonging to the same species found in the same area at the same time

Allele frequency

How often an allele of a gene occurs in a population

Gene pool

All alleles in a population

Identifying genotype of dominant phenotype

Cross with a homozygous recessive

Presence of recessive phenotype in offspring identifies heterozygous genotype in the parent

What the hardy-Weinberg principle predicts

Looks at allele frequency within populations

Predicts that the frequency of the allele of a gene in a particular population will stay the same from generation to generation

5 conditions where hardy Weinberg principle is valid

• population is large

• No immigration or emigration

• all genotypes have equal reproductive success

• Mating is random

• No gene mutation.

Hardy Weinberg equations

p² + q² + 2pq = 1

p + q = 1