Exam 3 - Review Flashcards
The study of distribution and change in frequency of alleles within populations.
Populaiton genetics
A change in gene frequency over time in a population (i.e. leads to speciation and divergence).
Evolution
of individuals possessing the genotype over the total # of individuals in the sample.
Genotypic frequency
of copies of a particular allele present in a sample over the total # of alleles
Allelic frequency
States that allele and genotype frequencies are constant within a population from generation to generation (i.e. Absent of other evolutionary influences).
Hardy-Weinberg Law
Assumptions of Hardy-Weinberg Law.
Population = Large, Mating = Random, Mutations/Migration/Natural selection = Not present
Measure of probability, determines whether two alleles are identical by descent
Inbreeding
Alleles descended from the same copy in a common ancestor (i.e. seen in inbreeding, small populations).
Alleles identical by descent
The avoidance of mating between related individuals.
Outcrossing
Conditions that favor inbreeding.
Can uncover/eliminate harful alleles. Can preserve good combinations of genes that may otherwise be broken up by outcrossing.
Observance of different rates of survival/reproduction due to differences in phenotype.
Natural selection
Phenomena where two individuals have a higher probability of mating as opposed to the rest of the individuals in the population.
Nonrandom mating
A permanent alteration in the DNA sequence that makes up a gene.
Mutation
Movement of a group/population/individual.
Migration
A change in the frequency of an allele in a small population, due to chance disappearance of particular genes (i.e. individuals die do not reproduce)
Genetic drift (i.e. bottleneck effect and founder effect)
Natural selection, nonrandoming mating, mutaiton, migration, and genetic drift are all forces of what?
Evolution
Phenomena that occurs when members of one biological sex compete in order to choose mates of the other sex to mate with.
Sexual selection
Potential effect of introducing genes from an outside populaltion into another population.
Dramatic change in allele frequency.
What happens when the environment of a population changes?
Population will adapt to new environment through natural selection or will suffer.
Why are the characteristics of a small isolated population useful for genetic studies?
Can be utilized to study/identify rare disease variants. Have a reduced genetic diversity some of which drift to a high frequency of a rare disease.
Relative intensity of selection against a genotype.
Selection coefficient
Phenomena where heterozygotes are favored over homozygotes (i.e. provide a reproductive advantage) thus both alleles are maintained in a population.
Overdominance/Heterozygote advantage
A genetic change in a group of organisms, a change in gene frequency within a population.
Biological evolution
Type of biological evolution, takes place in a single group/lineage with the passage of time.
Anagenesis
Type of biological evolution, splitting of one lineage into two leading to arise of new species.
Cladogenesis
Reproductive isolating mechanism, acts before zygote has formed.
Prezygotic
Reproductive isolating mechanism, acts after zygote has formed.
Postzygotic
Examples of prezygotic reproductive isolating mechanisms.
Ecological (i.e. differences in habitats thus individuals do not meet); Temporal (i.e. reproduction takes places at different times)
Postzygotic, hybrid zygote does not survive to reproduction.
Hybrid inviability
Postzygotic, hybrid is steril.
Hybrid sterility
Postzygotic, first generation is viable and fertile, but second generation is inviable or sterile.
Hybrid breakdown
The evolutionary relationships among a group of organisms.
Phylogeny
Most prominent idea today, states that populations that were able to deal with a rapidly change environment survived best (i.e. ability to make tools, social structure, and upright walking)
Variability selection hypothesis
Protein evolution is relatively constant therefore observation of the amount of molecular change can be used as a clock.
Molecular clock
Functional domains encoded by individual exons can be shuffled to create mosaic genes of different but related function.
Exon shuffling
Tumor remains localized.
Benign tumor
Tumor cell invades other tissues.
Malignant tumor
Tumor cell induces secondary tumors
Metastasis
Notion that a singlular mutaiton event is not in of itself the result of cancer but rather it is an accumulaiton of issues.
Knudson’s multistep model of cancer
Two somatic mutations in a cell leading to a tumor.
Sporadic cancer
Person is predisposed to cancer (i.e. inherits one mutation) only one somatic mutation is required to produce cancerous cells.
Hereditary cancer
Initiating event of sporadic cancer.
May be deregulation of growth-regulating genes leading to DNA damage and DNA replicaiton stress
Initiating event of sporadic cancer.
Genomic instability
Most cancers (i.e. if not all) have a genetic basis yet few are hereditary. Why is this the case?
Cancer tends to result as an individual ages and is exposued to carinogens. These mutations are commonly occ
Deals with phenotypes that vary continuously (i.e. such as height or mass).
Quantitative genetics
Phenomena that describes that control of quantitative characteristics being controlled by the sum effects of multiple genes
Polygenic inheritance
What would have happened if he studied traits with continuous phenotypes?
He would not have been able to make that mathematical conclusions he derived from his studies.
Demonstrated as only two possible phenotypes (i.e. present of absent) although they are quantitative. As susceptibility increases and reaches threshold the phenotype will be present
Threshold characteristics
Graph that displays the # or proportion of different phenotypes.
Frequency distribution
Average of a set of values.
Mean
Information provided via mean.
Approximate center of distribution.