CH23 Flashcards
Define
Microevolution
Change in allele frequencies in a population over generations
What are the causes of microevolution?
Most important:mutations. There is also natural selection, genetic drift and gene flow
Define
Genetic drift
Chance events that alter frequencies
Define
Gene flow
Allele transfer between populations
Define
Gene pool
All the genetic variants within a population
Define
Genetic variation
Differences amongst individuals in the composition of their genes or other DNA sequences
Define
Phenotype
Observable traits such as appearance, development, behavior
What is phenotype a product of?
It is a product of inheritance (many genes for one trait) and environmental influences. Not everything is passed on as inheritance.
In what cells must mutations occur to form new alleles?
Mutations must occur in cell lines for gametes for them to have any impact on the phenotype
How else can gene number and position change?
- Duplication because of meiosis errors (small errors aren’t harmful but may compounds over generations)
- Slippage during DNA replication
- Transposons
How does sexual reproduction impact genetic/phenotypic variation?
Alleles are shuffled, producing individual genotypes
1. crossing over
2. independent assortment
3. fertilization
Define
Fixed (in regards to populations and alleles)
If there is one allele for one locus in all members of a population, the allele is said to be fixed
What are the criterion for a population to be at Hardy-Weinberg equilibrium?
- No mutations
- Random mating (ex: no incest preferably)
- No natural selection
- Large population size (and little genetic drift)
- No gene flow
Can populations be at HW equilibrium for a single gene?
Yes, populations can be in HW equilibrium at some loci in particular
