Genetic and Phenotypic Variation Flashcards

This set of vocabulary flashcards covers key concepts from the lecture on genetic and phenotypic variation, fitness definitions, non-genetic variation sources, and the Hardy-Weinberg principle.

Evolution

The change in inherited characteristics of a population or species.

Mutation

An alteration of DNA sequence which may or may not result in the alteration or origin of alleles and may change the phenotype.

Fitness (Molecular Perspective)

The average contribution of an allele or genotype to the next generation.

Fitness (Organismal Perspective)

The number of offspring produced.

Phenotype

All features of an organism except DNA sequences, including proteins, transcription of genes, morphology, behavior, and life histories.

Congenital effects

Environmental effects that cause phenotypic variation without a genetic basis.

Maternal effects

A special case where variation in offspring phenotype is the result of nongenetic influences directly from the mother, such as yolk allocation in eggs, maternal care, and physiological condition.

Environmental variance

The general term for environmental effects that contribute to phenotypic variation.

Fluctuating asymmetry

A measurable difference on the left and right side of the body caused by random events at the molecular level during development.

Variance

The average squared deviation of observations from the mean, used to quantify genetic influence on a trait.

Phenotypic variance ($V_P$)

The sum of genetic variance ($V_G$) and environmental variance ($V_E$), expressed as $V_P = V_G + V_E$.

Broad-sense heritability ($H^2$)

The proportion of phenotypic variance that is genetic, calculated as $H^2 = \frac{V_G}{V_G + V_E}$.

Allele frequency

The proportion of copies of a specific allele in a population.

Homozygous

A condition where the inherited alleles for a genotype are the same.

Heterozygous

A condition where the inherited alleles for a genotype are different.

Genotypic frequency

The proportion of the population that has a certain genotype.

Panmictic

A term describing a population where mating is random.

Hardy-Weinberg principle

A testable foundation for mechanisms of evolutionary theory which predicts that genotypic frequencies will equal $p^2 + 2pq + q^2 = 1$ under specific assumptions.