Quantitative and Qualitative Genetics Flashcards
a set of individuals which can breed within the group but cannot outside of it.
Species
a group of individuals within a species which live together.
a population
Sum total of all alleles in the breeding members of a population
Gene pool
One species splits into two with related individuals which can no longer interbreed.
Speciation
There are five basic Hardy-Weinberg assumptions:
no mutation, random mating, no gene flow, infinite population size, and no selection.
chance events contribute to the elimination of alleles or drastic change in allelic frequencies. Each individual has an equal chance of being affected, and random circumstances decide which individuals will survive to contribute their alleles to the population.
Genetic drift
Gene Flow
allelic exchange between populations. Immigration (bringing in an individual from the same species but a different population) potentially increases the gene pool to which it is introduced.
Natural selection
particular alleles or allelic combinations mean that individuals are more likely to produce offspring, who in turn will reach breeding age. This is related to the classic “survival of the fittest” often put forward as Darwinian Theory. However, considering that populations expand and migrate to new climates, natural selection is more along the lines of survival of the ones who adapt the fastest (closer to Darwin’s actual theory).
individuals in populations and species often have mating preferences. Self-fertile species don’t have a random option.
Non-random mating
Mutation
the generation of new alleles by actual change (a biological or chemical error) at the DNA sequence level.
VP = VE + VG + VGE
Explain the variances above?
Where:
Vp = total phenotypic variance
VE =phenotypic variance due to environment
VG =phenotypic variance due to genetics
VGE = phenotypic variance due to interactions of environment and genetics
Broad Sense heritability
The broad-sense heritability of a trait is the proportion of phenotypic variance attributable to genetic causes,
Narrow sense heritability
narrow-sense heritability is the proportion attributable to additive gene effects.
Qualitative Genetics
simple/single allele or alleles contibute to something such as colour. nil phenotypical range, it either is phenotypic for a particular trait or it is not. dwarfism or normal for example.
Quantitative Genetics
Multi set of alleles that contribute to something like height or weight/yield. progeny sit in a bell curve of phenotypical range.
