Zusammenfassung der Ressource
Population Genetics
- In a population there are many
different phenotypes, proteins, and
alleles (DNA)
- Allele frequencies vary from population to population
- Africans have a high
frequency of the sickle
cell allele, Northern
Europeans have a high
frequency of the cystic
fibrosis allele, Ashkenazi
Jews have a high
frequency of the Tay
Sachs allele
- Hardy-Weinberg Law
- Frequencies of alleles
of the same gene will
remain the same from
generation to
generation provided:
that population is
infinitely large, mating is
random, selection is not
occurring, no mutation ,
no migration
- Problem: populations vary in size
- Genetic Drift
- Random changes in
gene frequencies due
to chance; seen in
small populations
- Causes
- Size is small over a
long period of time
- Founder Effect
- Bottleneck Effect
- Genetic bottleneck:
some genotypes do
not survive
- Problem: there are many
situations where mating is not
random
- Positive Assortative
mating, Negative
Assortative mating
- Problem: inbreeding
- Preferential mating
between close relatives.
Often a necessity if the
population is small
- Problem: Endogamy
- Marrying within a group