GENETIC DRIFT

textbook chapter 9.4

random genetic drift

the occurrence of characteristics in a population as a result of chance rather than natural selection

where does random genetic drift have the biggest impact

small populations

why does random genetic drift have a big impact on small populations

• small population is less representative of the alleles in the gene pool

• making them more likely to be affected by a change in the allele frequency

founder effect

a type of genetic drift where a new population is formed by a small number of individuals

• these individuals move away from the homeland to a new area

what can the groups have in founder effect

• a different allele frequency to the original population

• decreased genetic variation

bottleneck effect

a type of genetic drift that occurs when the size of a population is severely reduced due to a sudden event such as a natural disaster

what is the impact of bottleneck effect?

• allele frequency of survivors may not reflect that of the original population

how does genetic drift differ from natural selection?

survival from genetic drift occurs due to chance, rather than a specific trait