Chapter 5 Vocab Flashcards
Population Genetics
The study of evolutionary processes by modeling/testing how allele frequencies within a population change over time
Microevolution
a change in allele frequency in a population over generations
Macroevolution
broad pattern of evolution. The bridge mechanism of by new species originate from exsiting ones
Population
group of individuals within a enviroment of the same species or geneotypes
Hardy-Weinburg Equlibrium
The relationship between allele and genotype frequency in a population
Infinite alleles model
Each new mutation generates a new allele
Stepwise mutation model
(Microsatellites) mutations increase and decrease allele length by one unit with equal probability
Sequence divergence
The number of changes that distinguish two or more homologous DNA or protein sequences
Jukes-Cantor Model
The simplest model of sequence evolution. Assumes the same probability of base substitutions for each transition and transvertions
General Reversible Model
The most complex model of sequence evolution. This model takes in the account of base composition of DNA sequence. Puts values on all transition and transversion
Base Composition
The proportion of the 4 bases in a given DNA sequence. GC content
Hitchhiking
the increase of a neutral allele as a result of positive selection for a linked allele
Genetic Drift
the fluctuation of alleles in a finite population due to chance events
Wright-Fisher Model
Describes genetic drift in a finite population with the assumptions of HWE.
Effective population size (Ne)
the number of people in idealized Wright-Fisher population that experience the same amount of genetic drift
Census Size
Direct representation of a population
Fixation
An one allele is positivitlely selected for within a population and other alleles eventually become extinct
Founder effect
Genetic drift that shows a subpopulation moving to a new enviroment and becoming a seperate population of their own
Bottleneck effect
A chance event that randomly selects allleles while others become extinct
Fecundity
then number of offspring
Subpopulation
A randomly mating population that exchange migrants with other populations to form a metapopulation
Metapopulation
A group of populations connected through migration
Genetic Differentiation
the procees where the genetic composition of two or more populations isolated from one another diverges over time
Population Structure
The absence of random mating within a population. This will ultimately leading to being a metapopulation composed of subpopulations
Fixation Indicies
quotients used to analyze the departure of genotype frequencies from HWE
Assortative Mating
Like chooses like
Disassortative mating
increase heterozygotes and are chosen based on dissimiliarities
Outbreeding
reproduction involving distantly related parents
Inbreeding
reproduction involving genetically closely related parental types
Coefficient of kinship
probability of 2 alleles from 2 different alleles are related
Coefficient of relatedness
probabilting of randomly picking alleles that are related by common descent
Outbreeding depression
A reduction of fitness of offspring resulting from the mating of genetically different parents
Meiotic Drive
A process causing one type gamete to be over or under represented in the gametes formed.
Fitness
the ability to survive and produce viable offspring
Selection coefficient (s)
A quotient used to to compare the fitness of different genotypes
Negative Selection/ Purifying
Removing an allele from a population through natural selection
Positive Selection/ Diversifying
increase an allele in a population that increases fitness of an organism
Heterozygote advantage/overdominant selection
individuals in the mean benefit the most over the individuals in the extreme (heterozygotes)
Balanced polymorphism
Same amount of polymorphisms coming in and out of a population equally
Underdominant Selection
individuals in the extremes have a higher fitness than the individuals near the mean (homozygotes)
Frequency-dependent selection
Fitness of the genotype depends on the frequency in a population
Mate Choice
More abundant sex has choice for mates, and selects for desired traits
n-island model
describes migration. Shows the movement from one occupied are to another. All migration lengths are the same
Stepping stone model
builds on the n-island model by taking into account geographical distance to be a factor of migration
Isolation by distance models
A decrease of population similarity with geographical distance as a result of mating distances
Kin-structured migration
When migrating individuals are not a random sample from a source of population but are members of the same family
Mutation Drift Balance/Equlibrium
the number of mutations entering is balenced by the number of varients lost thru genetic drift
Population mutation parameter
The probability of 2 copies of the same nucleotide drawn at random from aset of sequences will be different from one another
Population recombination parameter
The expected level of LD in a randomly mating population
Advantagous allele
An allele that increases the fitness of of its carrier
Neutral allele
An allele that has no impact on the fitness of its carrier
Neutral theory of molecular evolution
A majority of mutations do not influence the fitness of their carriers
Outgroup
The taxon from a group that is know to be the earliest divergence of a common ancestor
Episodic selection model
Selection that is not constant over time
Nearly neutral model
a slight increase or decrease of an allele that slightly increases or decreases the fitness of an individual but not by much
