06.0 Pre-Class Vocabulary

Lecture 6

Fitness

The survival & reproductive success of an organism

Genotype

The entire genetic makeup of an organism

Phenotype

The observable characteristics of an organism

Pleiotropy

When a single gene affects the expression of more than one diff phenotypic trait

Antagonistic Pleiotropy

A mutation w beneficial effects for one trait that also causes detrimental effects on other traits

Negative Selection

A dec. in frequency of an allele. Occurs when the fitness of an allele is less than 1.

Positive Selection

An increase in the frequency of an allele. Occurs when the fitness of an allele is greater than 1

Epistasis

An allele’s effect at one genetic locus are modified by alleles at one or more other loci

Additive Allele

An allele that yields twice the phenotypic effect when two copies are present at a given locus than occurs when only one copy is present

Negative Frequency-Dependent Selection

Selection that occurs when rare genotypes have higher fitness than common genotypes

Heterozygote Advantage

Selection that favours heterozygous individuals over either the dominant homozygote or the recessive homozygote

Balancing Selection

A form of selection that favours more than one allele

Inbreeding Coefficient

The probability that two alleles at any locus in an individual will be identical b/c of common descent

Inbreeding Depression

This condition arises when rare recessive alleles become expressed in homozygous state & can detrimentally affect the fitness of individuals

Landscape Genetics

A field of research that combines population genetics, landscape ecology, & spatial statistics

Population Structure/Subdivision

This refers to the occurrence of populations that are subdivided by geography, behaviour, or other influences that prevent individuals from mixing completely

Genetic Distance

A measure of how diff pops are from each other genetically

Gene Flow

The movement or migration of alleles b/w pops

Relative Fitness

The relative success of a genotype standardized to the success of other genotypes in the pop