Topic 11 -Genetic Population Structure Flashcards
Genetic structure
A description of the genetic variation among individuals within a population
Remember genetic variation is important it reflects
The capacity of a population to respond/adapt to environmental change
Gene flow
The Exchange of genetic material among populations resulting from dispersal
Genetic variation depends on the _____________ Acting on individuals within a population
Variability of selection pressures
Few Selection pressures with low variability
Low variation
Many selection pressures with high variability
High variation
To quantify the level of genetic variation in a population we use level of heterozygosity which is
The proportion of heterozygotes in the population
The more alleles in the gene pool means more possible combinations of alleles which leads to a higher genetic variation
General pattern
Smaller populations tend to have lower genetic diversity or variation than larger populations
Two mechanisms operating to decrease genetic diversity over time
Genetic drift and inbreeding
Genetic drift
Random change in allele frequency’s within a population due to chance
Random -no discrimination between or selection of individuals with favourable or unfavourable traits
Chance -Unpredictable change in environmental conditions
Genetic drift occurs in all populations and is a mechanism of
Evolution
In small populations genetic drift occurs at a_________And is more likely to result in the _____________
Faster rate
Loss of allele
Inbreeding
Meeting between relatives
In small populations the choice of mates can be limited resulting in an increase probability of meeting with relatives
Inbreeding tends to increase_________ and decrease___________
Homozygosity
heterozygosity
If rare recessive genes are harmful
homozygosity for recessive genes can result in reduced fitness and increased mortality
