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Genetic trait with distinct phenotypes
What is nonrandom mating a deviation from?
What are reasons for non-random mating?
- Phenotypic resemblemce
- Genetic relatedness
What are the types of deviatons due to phenotypic resemblances?
- Positive assortment - tendency for like individuals to mate (ie: similiar heights)
- Negative assortment - tendency for unlike individuals to mate (ie: dissimiliar heights)
What genes does non-random mating due to phenotypic resemblence affect?
Only genes that encode these traits
What are the types of deviations due to genetic relatedness?
- Inbreeding: - preferential mating between related individuals
- Outbreding/Outcrossing: avoidance of mating with related individuals
What Are types of Assortment?
- Phenotypic resemblences
- Genetic relatedness
What are the effects of assortive mating?
- 1: Positive assortment and inbreeding increase homozygosity
- 2: Negative assortment and outbreeding increase heterozygosity
- 3:Genotype frequencies change, but Allele frequencies do not
What are the two causes of inbreeding?
- Mate choice:
- Population subdivision:
An individual whose parents are related
Two alleles that are identical by descent
Two alleles that are not identical by descent
What is the inbreeding coefficient?
(F): the probability that an individuals alleles are autozygous
What are the 5 effects of inbreeding on an individual?
- Increases homozygosity across genes
- Expression of recessive alleles
- (taboos and organisms that routinely inbreed)
Inbreeding 2 effects at a pop level
- Increased homozygosity relative to HW equilibrium
- Genotype frequencies change without changing allele frequencies
random change in the genetic material
What are the 2 types of mutation?
- Gene (point) mutation: produce new alleles
- Chromosomal mutation: produce new chromosomal arrangments
What is mutations importance in evolution?
- It is not significant on a generation-to-generation time scale
- It is the source of all novel genetic variation
"Mu" and "v" are directly proportional to _________.
Forward and backward mutational frequencies.
What are the 3 types of mutational equilibrium?
Migration vs Gene Flow
Same freaking thing
The non-random movement of alleles into or out of a population
What are the effects of migration?
Bring new alleles to the population -> bring new variation to gene pool
3 types of populations considered by migration are ________ and thier frequencies are__________.
- Native: with frequencies PnQn
- Source: PmQm
- Conglomerate: m+(1-m) (m= migration rate)
What are the two effects of migration?
- Conglomerate becomes native and a new migration event occurs
- Conglomerate/Native frequencies asymptotically approach those of the migrant population -> Qm=Qn
What is the "island model" for migration?
- Migration is 2 way
- There are many populations
- All populations can evolve
What are the 4 assumptions of the Island Model?
- All populations are on discrete "islands"
- All populations are equal in terms of size, migration rate, etc... (migration rate should remain constant)
- ...but p and q do not have to be the same in each pop at the start
- The number of populations is very large (infinite)
- Island distances are not a factor
Gene flow alters frequencies ____?____ populations.
Gene flow ___?___ genetic differences __?__ populations and is known as the "__?__."
- Great Homogenizer
Gene flow __?__ speciation which __?__.
- Requires Genetic Divergence
What eliminates the homogenizing effect of gene flow?
"Real" populations subject to genetic drift becuase _____.
- real pop are:
- finite and can be very small
Define: Genetic Drift
Random sampling error of gametes resulting in fluctuations in allelic frequencies from one generation to the next.
__?__ is another name for genetic drift.
Sewell Wright effect
Random sampling error is a result of __?__.
Observed outcomes that are different from expected probabilities due to random chance.
__?__ is a measure of random sampling error and gets __?__ as k gets __?__.
Genetic drift is __?__ so direction and magnitude cannot be __?__.
- Accurately Predicted
The long term effect of genetic drift is __?__
loss of one allele while the other becomes fixed
__?/?__ is a function of population site.
genetic drift causes variation among populations to __?__
The two special cases of genetic drift are __?__ and __?__.
- Bottleneck effect
- Founder effect
The Bottleneck Effect is __?__.
when populations undergo a drastic reduction in population size (N)
The bottleneck effect results in __?__ and __?__.
- change in allele frequency
- loss of genetic variation
How is variation lost from bottleneck restored?
Genetic flow/Migration or Mutation (very slow)
The Founder Effect is __?__
when a new population is established from a small number of "founders"
The founder effect results in __?__ and __?__.
- different allele frequencies in founder populations
- low variation in founder population