Genetic Diversity Flashcards
1
Q
Allele Frequency
A
Frequency of an allele in a population.
2
Q
Natural Selection
A
- random mutation can result in a new alleles of a gene
- many of these mutations are harmful, but in certain environments, the new allele of a gene might benefit the possessor
- a good allele leads to increased reproductive success
- the good allele is inherited by members of the next generation
- therefore, over many generations new allele increases in frequency in population
3
Q
The Founder Effect
A
- small group of individuals migrate away or become isolated from a population
- the founding pop. is only made up of a small group. Inbreeding is a problem as closely related
- may have a non-representing sample of alleles from the parent pop.
- the colonising pop. may evolve quickly/differently from original pop. especially if environment is different.
4
Q
Population Bottlenecks
A
- Ecological events may reduce pop. size dramatically
- Disasters that are unselective
- Small surviving pop. are unlikely to be representative of original pop
- By chance alleles may be overrepresented among survivors, some may be eliminated completely.
5
Q
Similarities between founder effect and bottlenecks
A
- both genetic drift, resulting in changes in allele frequency
- initially genetic diversity lost in both systems
- both involve small group breeding with each other (may be among close relatives)
- may result in a new pop which carries alleles that are unlikely to be a true representation of the original pop
6
Q
Differences between founder effect and bottlenecks
A
- bottlenecks: killed with regard for genetic composition (floods, fires).
- founder effect: small number of individuals separate from the larger parent pop. and establish a colony in the new place.
7
Q
Directional Selection
A
Curve moves left or right on graph depending on how adaptations help.
8
Q
Stabilising Selection
A
Curve more rounded, smaller, narrower
Fits to best norm
9
Q
Genetic Diversity
A
Variety of alleles within a species.
