Gene Pools (DP IB Biology: HL): Revision Note

Gene Pools

• A gene pool consists of all the genes and their different alleles, present in an interbreeding population

•  A consideration of all the genes (and alleles thereof) in a population is important as that will govern the genomes of the next generation

• Some populations of the same species are geographically isolated from each other

  • So multiple gene pools can exist for a species

Stable gene pools

• Populations retain a stable gene pool under the following conditions

  • The population is large

  • Each individual in the population has an equal chance of mating

  • That matings are random

  • There are no selection pressures acting upon individuals based on their phenotype

•  A stable gene pool means that a population is not evolving

Changes in Allele Frequency

• Darwin came up with the theory of evolution by natural selection without any knowledge of genetics or DNA

• His theory has been further developed by modern scientists through the integration of genetics

  • This is often referred to as neo-Darwinism 

• Modern science has allowed evolution to be understood at a molecular level
  

  • Changes in allele frequency in the gene pool occur due to processes such as natural selection, sexual selection and genetic drift