Week 22: Gene Flow Flashcards
define Gene flow
the process of alleles moving from one population to another
To make things simpler, we will always focus on the effect of gene flow INTO a population.
Question on page 4
Provide example of Gene flow (migration) … in plants!
pollen movement
seed movement
Effects of Gene flow on population
Can introduce new alleles to populations
Makes 2 populations more genetically similar
Benefits of gene flow
new alleles are introduced to a population with low diversity (can provide new variation for selection to act on)
Harmful effects of gene flow
can inhibit local adaptation in populations experiencing different selection pressures
In depth explaination:
Dilution of Local Adaptations: Gene flow can introduce alleles from one population to another, potentially diluting locally adapted gene combinations. If a population has evolved specific traits that are well-suited to its local environment, the influx of genes from outside populations may disrupt these adaptations.
Absence of gene flow allows for ….
Absence of gene flow allows the opportunity for independent genetic changes (different evolutionary trajectory)
Question on page 17
Does gene flow increase of decrease fitness in a population
IT DEPENDS (the impact of gene flow is context-dependent)
ex of increase fitness:
Introduction of Beneficial Alleles
ex of decrease fitness:
Introduction of Maladaptive Alleles
Disruption of Local Adaptations
DON’T HAVE TO REMEMBER THESE EXAMPLES JUST PROVIDED FOR MORE CONTEXT
Gene flow - Effect on genetic variation:
Increase within populations
*Question on page 20
*Question on page 23
how do we get an increase in genetic diversity in a species
Mutation
How does mutation increase genetic diversity in a species
Adds new alleles/genes to the population
Mutation - Effect on fitness:
Random (it depends), but often negative.
