Chapter 27 Flashcards
(35 cards)
What is a gene pool?
All alleles of every gene in a population
A large population is usually composed of smaller groups called?
Subpopulations or demes
They are far likelier to breed with each other than with general population
A population may change in what ways?
Size, geographic location, genetic composition
What does polymorphism mean?
Many traits display variation within a population
What is the formula for allele frequency?
Number of copies of an allele in population / total number of all alleles for that gene in a population
What is the formula for genotype frequency?
Number of individuals with a particular genotype in a population / total number of all individuals in a population
For a given trait, the allele and genotype frequencies are always less than or equal to what?
1
For monomorphic genes, allele will be close or equal to 1
For polymorphic genes, allele should add up to 1
What is the hardy Weinberg equation?
P^2 + 2pm + q^2 = 1
What are the conditions that need to be met for a population to be in equilibrium?
- No genetic drift - allele frequencies do not change
- Random mating
- No migration
- No natural selection
- No new mutations
What is micro evolution?
Changes in a populations gene pool from generation to generation
What is assortive mating?
When individuals are more likely to mate due to similar phenotypic characteristics
What is disassortive mating?
When individuals with dissimilar phenotypes mate
What is the formula for inbreeding (F)?
F = sum (1/2)^n (number of individuals in inbreeding path) x (1 + 0)
What is the fixation coefficient?
Another name for inbreeding
It is the probability that an allele will be fixed in the homozygous condition
What are the genotype frequencies with the fixation coefficient?
P^2 + Fpq = AA
2pq(1-F) = Aa
Q^2 + Fpq = aa
What is mutation rate?
The probability that a gene will be altered by a new mutation
How does mutation rate affect allele frequencies?
Mutation converts dom allele into rec allele, A->a
What is the formula to calculate the change in allele frequency after any number of generations?
(1- mutation rate (u)^number of generations (t) = frequency of allele after t generations / frequency of allele in starting generation
What is random genetic drift?
The random changes in allele frequencies due to chance fluctuations
Favors either loss or fixation of allele
How many new mutations are expected in natural populations?
2(mutation rate)(number of individuals in population)
What is the formula for probability of fixation?
1 / 2 x population
What is the formula for probability of elimination?
1 - 1/2 x population
If population is very large then …
New mutations are more likely to occur however also has a greater change of being eliminated
If population is very small then …
New mutations are less likely to occur but have a greater chance of being fixed
