Mutation and Genetic Drift

Genetic Drift

Random changes in gene
frequency from one generation
to another

Many either fix the allele
or lose it by chance

multiple alleles can't
be fixed or lost

Founder Effect

Chance deviation of gene frequency
from source population

Larger samples size
the smaller the deviation
from the average

Bottleneck effect

Dramatic reduction in population
size leading to reduced genetic
variability

Migration

Movement of individuals
between established
existing populations

Population genes become more alike
time goes on and migration is constantly
going back and forth between the two

Random change in an allele

1:1000-1:100000
of offsprings will have
a change in allele not
from the parent due
to mutation

Age Dependent

Higher rate of
mutations in
older parents

95% of mutations are
harmful for homozygous
genes

4% of mutations are
neither harmful or helpful

1% of mutations
are beneficial

Ultimate source of genetic variation

Good for environmental changes