L2 genetic basis for evolution

What is a genotype

Genetic information stored in an individual genes

How similar is DNA across cells in an individual

Mostly identical

Why do different tissues behave differently

Different gene expression

What type of DNA regulates gene expression

Non coding regulatory DNA

What are alleles

Alternative forms of a gene at a locus

What is a locus

Position of a gene in the genome

What does polygenic mean

Trait controlled by many genes

What is pleiotropy

One gene affects multiple traits

What is epistasis

One allele affects expression of another gene

What is phenotype

Observable characteristics of an organism

What contributes to phenotypic variation

Genetic and environmental factors

What is genetic variation

Differences in genetic makeup between individuals

What is additive genetic variance

Genetic similarity between parents and offspring

What contributes to non additive genetic effects

Dominance and gene interactions

How is heritability measured

By comparing parent and offspring similarity

What does h squared represent

Heritability of a trait

What is the range of heritability

Zero to one

What does high heritability mean

Trait strongly influenced by genetics

What does low heritability mean

Trait strongly influenced by environment

What is Fisher fundamental theorem

Traits linked to reproductive success are maximised by selection

What happens to variation in highly selected traits

It is reduced

Why is variability low in important traits

Non optimal variants are selected out

What type of variation remains in such traits

Non heritable variation

What evidence supports Fisher theorem in flycatchers

Traits linked to success had low heritability

What species was used in this evidence

Collared flycatchers

What was observed about important traits in flycatchers

Low heritability

What evidence supports selection in crops

Oil yield selection in corn

What are sources of genetic variation

Mutations and environmental changes

How do mutations contribute to variation

Create new genetic differences

How do changing environments contribute to variation

Maintain diversity through selection pressures

What role do pathogens play in variation

Drive genetic diversity through selection