Module 14 Flashcards
Quantitative Genetics
The study of quantitative traits, which can be anatomical, physiological, behavioral, and disease-related
Frequency Distribution
A normal distribution of quantitative traits following a bell-curve model
Polygenic Inheritance
Influenced by two or more genes, exhibits a continuum of phenotypic variation
Quantitative Trait Loci (QTL)
Location on chromosomes harboring one or more genes affecting the outcome of a quantitative trait, identified by genetic mapping
The more ____ and ____ variability of a quantitative trait, the greater phenotypic variance will be presented
genetic and environmental
QTLs are mapped by:
- Taking two highly inbred strains of diploid species
- Producing heterozygous F1 offspring
- Then backcrossing the F1 to the parent generation to produce the F2 offspring
- Identify which genes are associated with a specific phenotype
Heritability
The amount of phenotypic variation within a group of individuals due to genetic variation
Can be either broad or narrow sense
Broad Sense Heritability
Takes into account different types of genetic variation possibly affecting phenotype
Narrow Sense Heritability
Heritability of a trait based on additive (genetic) allelic effects
Genotype-Environment Interaction
Certain environmental factors can positively influence some genotypes (ex. plants and mineral content of soil)
Genotype-Environment Association
Certain genotypes can be preferentially found in specific environments (ex. studied in genetically identical twins)
Selective Breeding
Modification of phenotypes in plant and animal species of economic importance by human intervention (artificial selection)
Selection Limit
Selective breeding for certain phenotypes plateaus once an individual becomes monomorphic for all relevant alleles (ex. corn oil content)
Heterosis
When two inbred strains are crossed to each other, offspring are more vigorous than either parent (“hybrid vigor”)
Dominance Hypothesis
Proposed by Davenport, effects of dominant alleles explain the favorable heterozygote outcome