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Genes

Behavior Genetics

Genes

Alter nervous system &

physiology

Alter behavior

Environment

Alter gene expression

+Basic Genetics

Read pp. 28-30, and refresh your memory

+Goals of Behavior Genetics

identify gene (genes) that control behavior

identify gene interactions with products and environment

Measure heritability – statistical measure that indicates how strongly a behavior is influenced by genes. Varies from 0 – 1, where 0 is no heritability

Requires lots of individuals, often families

+Goals of Behavior Genetics

Genomics – study of an organism’s entire genome. Functional – know all coding and

noncoding genes Comparative – compare genomes in

different species to get at evolution Proteomics – know all proteins coded for

by an organism’s genes, how they work together, and influence traits

+Methods

Rule out environmental effects

INBRED lines – homozygous at all loci. Can compare 2 lines to get at environmental vs gene effects

+Methods

Artificial Selection If you can

select, it must be genetic

Rule out environmental effects EX: House Mice

+Methods

Induce Mutation dunce in fruit

flies a memory

problem

Rule out environmental effects EX: Fruit Flies

+Methods

Natural variation / hybridization

One gene – multiple traits; gene networks

Rule out environmental effects EX: Fruit Flies

+Behavioral Variation and Genes

Genes – variation in alleles

Gene regulation

Relating this to humans and autism

+Environmental Regulation

However, environment still has an effect; there is a gene – environment interaction

Read the examples on cichlids and songbirds

+Environmental Regulation

Sneakers vs. immature males Same age Larger gonads,

smaller body size, male body scent

Different genes expressed in brains

+Environmental RegulationGene Networks

Different networks in different environments

+Epigenetics

two methods DNA methylation histone

acetylation

Stable alteration in gene expression without changes in DNA sequences

affect how tight the DNA molecule is

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