Evolution - Lecture 8, Microevolution Flashcards
What is microevolution?
Changes in the gene pool of a population of organisms over time
What is macroevolution?
Evolution on a bigger scale
Major evolutionary events above the level of species, such as evolution of major animal groups
What is a gene pool?
The alleles of all genes of all individuals of a population
What is population genetics?
The study of microevolution
How is population genetics used to study human pathogens?
Can use it to study:
Antibiotic resistance
Virus resistance to antiviral drugs
Emerging new pathogens
How is population genetics used to study the genetic structure of wild populations?
Tells us how diverse a population is
Tells us how this diversity is distributed
The response of population to changes, eg climate change
How do population geneticists study?
They use a sample of the gene pool
They look at one gene at a time
What are the two types of frequency that population geneticists look at?
Allelic and Genotypic
What is allelic frequency?
Worked out using:
Number of allele of one type
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Total number of alleles
What is genotypic frequency?
Worked out using:
Number of individuals of one genotype
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Total number of individuals
What is the Hardy-Weinberg equilibrium?
Over time the allelic and genotypic frequencies will reach equilibrium and stop changing
p2 + 2pq +q2 =1
What conditions are needed for Hardy-Weinberg equilibrium to apply?
Large population size
Random mating
No migration from other populations
No mutation
No selection
What are the factors leading to changes in allelic and genotypic frequency?
Genetic drift
Small population size
Non-random mating
Migration/gene flow
Selection
How is genetic variation of a population preserved using natural selection?
Balancing selection, for example heterozygote advantage and frequency dependant selection
Different selective pressures across the geographic range the population covers
How is the genetic variation of a population preserved using neutral theory?
Many alleles are neutral, which means they can’t be selected
Their frequencies will fluctuate randomly over time, causing genetic drift and enabling variation
