Conservation of Genetic Resources: Population Genetics

Study Notes

Population Genetics

Population genetics is the study of genetic variability by describing changes in allele frequency for a particular trait over time and analyzing the causes of those changes.
It is the application of Mendel's laws and other genetic principles to entire populations of organisms instead of just individuals.

Definitions

Phenotype: describes all traits of an individual concerning its morphology, physiology, ecological relationships, and behavior.
Genotype: is the description of the complete set of genes that an individual inherits from its parents.
Gene: the basic physical and functional unit of heredity, passing information from one generation to the next.
Allele: any of the alternative forms of a gene that can exist at a single locus.
Allele frequency: the proportion of all alleles of that gene in the population that are specifically this type.
Genotype frequency: the frequency of a given genotype in a population.

The Hardy-Weinberg Principle

States that sexual reproduction does not reduce genetic variation generation after generation; on the contrary, the amount of variation remains constant if no disturbing forces are acting against it.
Assumes:
- Sexual reproduction
- Non-overlapping generations
- Random mating
- Very large population size
- Negligible migration
- No natural selection
- No mutations

Reproduction and Mating Systems

Inbreeding coefficient (F): measures the reduction of heterozygosity
H: actual frequency of heterozygotes in the population
H0: expected number of heterozygotes under random mating

Forces Shaping Genetic Diversity

Mutation: the ultimate source of variation, may be caused by spontaneous mutation or damage by radiation or chemical mutagens
Migration: increases diversity, rate of change in gene frequency is proportional to the difference in frequency between the recipient population and the average of the donor populations
Recombination: generates new combinations of existing diversity, does not create new diversity
Selection: acts on the inherited ability of organisms to survive and reproduce, leading to an increase in superior genotypes

Genetic Drift

Homozygosity: fixation and loss of alleles
Subpopulation differentiation: leads to genetic drift
Bottleneck: develops when the population size sharply drops, leading to loss of alleles
Founder effect: occurs when a few individuals colonize and become established in a new environment, leading to genetic drift
Population size: affects genetic diversity, heterozygosity declines with smaller population size
Allele loss: occurs at a rate dependent on population size and allele frequencies

Description

Test your understanding of the fundamental concepts of genetic diversity, including the Hardy-Weinberg principle, reproduction and mating systems, and forces shaping genetic diversity. This quiz covers the basics of population genetics and its importance in conservation of genetic resources.