Flashcards in Lesson 11 Population Genetics Deck (44)
Total of all genes within a particular population
A group of individuals of the same species that are capable of interbreeding with one another. Dynamic units that change size, location and genetic composition.
Many traits display variation within a population, either phenotypically or genetically.
Exists as two or more alleles in a population
Exists predominantly as a single allele in a population. Found in 99 percent or more cases.
No. Of copies of allele in population/
Total no. Of all alleles for that gene in population
Relative percentage of an allele of a given green
No. Of individuals with a particular genotype in a population/
Total number of individuals in a population
Relative percentage of a given genotype
Use of hardy-Weinberg equation
Used to calculate genotype frequencies based on allele frequencies
Hardy Weinberg equation
p^2 + 2pq + q^2 = 1
p^2 = genotype frequency of AA
2pq = genotype frequency of Aa
q^2 = genotype frequency of aa
What conditions must be met for Hardy Weinberg equation to work?
Large population, random mating, no migration, no natural selection, and no mutations
When two individuals are more likely to mate due to similar phenotypic characteristics
When unlike phenotypes mate
When two genetically related individuals mate with each other
Mating between unrelated individuals
coefficient of inbreeding (F)
F = Sum (1/2)^n (1 + Fa)
n = number of individuals in the inbreeding path
Fa = inbreeding coefficient of the common ancestor
Inbreeding: common ancestor
Someone who is an ancestor to both fo an individual's parents
Size of inbreeding path
The shortest no. Of steps through the pedigree that includes both parents and the common ancestor. Calculated by adding together all of the individuals in the path except for the individual of interest.
Measuring effects of inbreeding at population level
Frequency of AA= p^2 + Fpq
Frequency of Aa = 2pq (1-F)
Frequency of aa = q^2 + Fpq
What is effect of inbreeding
Lower the relative number of heterozygotes
Two types of evolutionary forces
1. Neutral forces
2. Adaptive forces
Alter allele frequencies in a random manner. Without regard to survival of the individual.
"select" for the survival of individuals who possess alleles that make them well adapted to their environment
What do new mutations provide a population?
Likelihood that a gene will be altered by a new mutation; expressed as the number of new mutations Ina given gene per generation
10^5 to 10^6 per generation
Random genetic drift
Random changes in allele frequencies due to sampling error
What does rate at which allele becomes fixed depend on?
Probability of fixation
1/2N (assuming an equal no. Of males and females contributing to the next generation)
Probability of elimination
1 - 1/2N
time it will take for fixation to occur
Mean t = 4N
Mean t = average no. Of generations to achieve fixation. N equals the no. Of individuals in a population.