W1 quantitative+ W2 plasticity Flashcards
What are quantitative traits?
Quantitative traits are traits which show a continuous phenotypic distribution controlled by many
genes. They are influenced by both genetic and environmental factors.
What factors determine phenotypic variation in quantitative traits?
Many genes + environmental factors
How would you determine whether phenotypic variation in a quantitative trait was due
to genetic or environmental variation?
By using genomics to measure the levels of genetic variation in the genes that controls the trait of interest or through transcriptomics which measures the changes in expression of functionally important genes.
What is the narrow-sense heritability of a trait?
- an estimate of the extent to which phenotypic variation of a trait can be explained by genes that have a additive genetic variance.
- Provides an estimate of the adaptive potential of a population
What is the broad sense heritability
of a trait?
the amount of genetic determination of a trait, for that specific trait, that particular pop, that particular environment
What is phenotypic plasticity?
The immediate phenotypic response to environmental cue or change, where individuals with the same genotypes have varied phenotypes in different environments
What is a reaction norm?
describes the degree of phenotypic plasticity i.e. the extent to which individuals can change their phenotype in response to changing environmental condition
Over what timeframes can plasticity operate? Illustrate your answer with an example.
Plasticity can operate between populations as well as within and across generations. Trans generational and intro-generational.
Why might plasticity be adaptive? Illustrate your answer with an example
Allows response to environmental change immediately- dont have to evolve and maintain fitness. Buffers populations from sudden enviro changes so that they can maintain fitness while waiting for evolution to occur.
Can we predict which species/populations will be more plastic? Explain your answer.
No we cant predict plasticity. Can speculate which species may be more plastic due to varied environements but cannot definitely determie
what is evolution?
A change in allele frequency Species response to climate change
extinction, migration or adaptation
What are the two types of genetic diversity?
- Adaptive genetic variation- genes that code for proteins, dev processes or influence organisms response to envrio and provides insight into process of adaptive evolutionary change
- Natural genetic variation- part of genome where no selection, informs us on processes like migration, drift, pop size
What are the 4 evolutionary forces that change allele frequency?
Act in divergence- mutation, drift, selection
Act in convergence isolated pops- migration, selection
Why is HW important?
Crucial in conservation and evolutionary genetics. Provides basis for detecting;
- deviations from random mating
- finite pop size
- selection
What are the 5 essential HW assumptions?
- Random mating
- infinite population size
- no selection
- No mutation
- No migration
What is an ANOVA?
a test that can be used to statistically test for plasticity and genetic variation in plasticity
Pop? is there significant variation between pops for this trait
Treatment? is there significant plasticity in response to treatment/environment?
Pop x treatment? Do the plasticity responses if the two diff pops differ significantly
How do you measure heritability?
- Family studies
- parent offspring regression b= heritability - Half sub-full sib- separate offspring to diff envrio
- diffs among siblings= enviro
- diffs between families= genetic - Animal model
- pedigree analysis- estimate quantitative genetic parameters in wild pop
- more powerful than half/full sib as can see all related individuals
What are maternal effects?
They are mothers profound influence- best use estimate additive genetic variance if use only fathers data
What are parent offspring regressions?
used to estimate heritability- assumes resemblance is due to gene equally inherited from both parents though may also be due to shared environment
What is cross-fostering?
- used to estimate heritability
- eggs/switched raised by foster parents
- phenotypic values regresses to genetic parents or foster and determine if genetic or envrio causes
What are reciprocal transplant experiments used for?
To distinguish between genes and effects of environment, determine if there is significant genetic difference between pops from diff enviros- move individuals to diff enviro. if difference is due to gene then enviro will have no effect
What is the relationship between plasticity and climate change?
Response to enviro change can be both plasticity and environmental change- still don’t know if evolution of plasticity is linked to environmental variability, thus cant predict which pops will be more/less plastic.
What does adaptive evolution of quantitative traits need?
- phenotypic variation
- Genetic basis of variation (heritable)
- Variation= diff fitness
- Survival linked fitness
