Quantitative Genetics - Chapter 28

These flashcards cover key vocabulary related to quantitative genetics, including definitions and relevant concepts.

Phenotype

The observable physical or biochemical characteristics of an organism, as determined by both genetic makeup and environmental influences.

Quantitative Trait

A characteristic that is measured on a continuous scale and is influenced by multiple genes and environmental factors.

Continuous Variation

Variation in a trait that does not fall into distinct categories and encompasses a range of phenotypes.

Polygenic Inheritance

Inheritance of a trait that is controlled by multiple genes, resulting in a continuous range of phenotypes.

Variance

A statistical measurement that describes how much the values of a set of observations differ from each other, particularly how far each number in the set is from the mean.

Normal Distribution

A probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean.

Heritability

The proportion of observed variation in a particular trait among individuals in a population that is attributable to genetic factors.

Broad-Sense Heritability (hB2)

The ratio of the genetic variance (VG) to the total phenotypic variance (VP), considering all genetic effects.

Narrow-Sense Heritability (hN2)

The proportion of phenotypic variance that can be attributed to the additive effects of alleles.

Correlation Coefficient (r)

A measure of the strength and direction of the relationship between two variables, ranging from -1 (perfect negative correlation) to +1 (perfect positive correlation).

Environmental Variance (V_E)

The proportion of the total phenotypic variance that is due to environmental factors.

Genetic Variance (V_G)

The proportion of the total phenotypic variance that is due to genetic differences among individuals.

Additive Genetic Variance (V_A)

The component of genetic variance due to the average effect of alleles, which is primarily responsible for the resemblance between relatives and response to selection.

Dominance Genetic Variance (V_D)

The component of genetic variance due to interactions between alleles at the same locus (dominance effects).

Epistatic Genetic Variance (V_I)

The component of genetic variance due to interactions between alleles at different loci (epistatic effects).

Reaction Norm

The pattern of phenotypic expression of a single genotype across a range of environments.