•A population is any group of members of the same species in a given geographical area.
•Gene pool refers to the collection of all alleles in the members of the population.
•Population genetics refers to the study of the genetics of a population and how the alleles vary with time.
# of particular allele /total # of alleles
•count both sets of the diploid chromosome of each individual
•Allele frequencies affect the genotype frequencies or the frequency of each type of homozygote and heterozygote in the population.
Frequency of a trait is determined from observation and varies in different populations. i.e. PKU: phenylketonuria, an inborn error of metabolism that causes mental retardation unless the person follows a special low protein diet from birth
DNA finger printing techniques