Unit 7: Quantitative genetics evolution test 2

Quantitative traits

Phenotypes influences by multiple genes and the environment

Phenotypic plasticity

Changes in a phenotype produced by a single genotype in different environments

Quantitative genetics

Study of the genetic mechanisms of continuous phenotypic traits

Polygenic trait (complex trait)

Influenced by many genetic loci

Epistasis

Interaction between alleles at different loci

Phenotypic plasticity

Interaction with the environment

Variance

Statistical measure of the dispersion of trait values about their mean

Broad sense heritability

Refers to the proportion of the total phenotypic variance that is attributable to genetic variation among individuals

Heritability

The proportion of phenotypic variation due to genetic variation

Narrow-sense heritability

The proportion of phenotypic variance explained by additive genetic variation

Directional selection

Favors individuals at one end of the distribution of phenotypes in the population

Stabilizing selection

Favors individuals in the middle of the distribution of phenotypes present in the population

Disruptive selection

Favors individuals at both tails of the distribution of the phenotypes present in the population

Selection differential,S,

Describes the difference between the mean of the reproducing members of the population that contribute offspring to the next generation and the mean of all members of the population

Evolutionary response, R

Describes the change in the mean phenotype from one generation to the next due to selection

Quantitative trait loci (QTL) analysis or mapping

The method that allows us to link the evolution of quantitative traits to their genetic basis

QTL

Stretches of DNA that are correlated within variation in a phenotypic trait, these regions contain genes or linked to genes, that contribute to population differences in a phenotype

Genome wide association mapping

Involves scanning through the genome of many individuals, some with and others without, a focal trait of interest, to search for markers associated with expression of the trait

Phenotypic plasticity

The capacity for a genotype to express more than one phenotype, depending on environment

Reaction Norm

Refers to the pattern of phenotypic expression of a single genotype across a range of environments

We can visualize the response of organisms to the environment by using a diagram called ____

Genotype-by-environment interactions (GxE)

The way an individual responds to the environment is variable and heritable