Animal Behavior Module 2

Genetic Predisposition

Innate tendency of different species to react differently to the same stimulus (e.g., dog barks vs. rabbit cowers).

Behavioral Genetics

The study of how genes influence and determine animal behavior.

DNA Nucleotide Components

Deoxyribose sugar, a phosphate group, and a nitrogenous base

Transcription

Process of making a single-stranded mRNA copy from a DNA template in the nucleus.

Translation

Process where ribosomes read mRNA codons to build a protein in the cytoplasm.

Regulatory Genes

Genes that produce transcription factors to turn other genes on or off.

Heritability

Statistical ratio showing how much behavioral variation in a population is due to genetic differences.

Inbreeding

Breeding close relatives to create homozygous lines, eliminating genetic variance to isolate environmental effects.

Artificial Selection

Selecting and breeding individuals with a specific behavior over generations to prove a genetic basis.

Candidate Genes

Genes suspected of causing a specific behavior based on literature or genome comparisons.

Knocking Up

increases gene expression

Knocking Down

disables/mutes a gene.

QTL (Quantitative Trait Locus)

The specific chromosome region where genes controlling a complex, multi-genic behavior are located.

Microarray Analysis

Monitoring thousands of mRNA molecules at once to see which gene networks turn on or off

Fruitless (fru) Gene

Controls fruit fly courtship; expressed in males to build mating circuits, while the required interneurons die in females.

Lynch Mouse Study

Artificially selected mice for nest-building; high-line built huge nests and low-line built tiny ones, proving a genetic basis.

Dunce Mutation

Mutant fly gene causing abnormal cAMP levels, which blocks the formation of long-term memories.

Female Mouse Social Recognition

Requires 4 interacting genes (estrogen alpha/beta, oxytocin, oxytocin receptor) to process social cues.

Vole Mating Basis

Prairie voles are monogamous due to high vasopressin receptors in brain reward centers; meadow voles lack them and are polygamous.

Cichlid Fish (A. burtoni) Status

Dominant males are colorful and territorial; subordinate males are camouflaged, fast-growing, and non-territorial.

GnRF Gene

Activated when a cichlid becomes dominant; enlarges hypothalamic cells, grows testes, and changes skin color.

Somatostatin

Hormone turned ON in dominant cichlids to halt body growth so energy shifts to reproduction.

Early Gene 1 (erg-1)

Instantly activates when a subordinate cichlid sees a dominant rival is gone, sparking a quick dominance transition.

Zenk Gene

Forebrain gene in songbirds that spikes in response to hearing a new song from its own species; vital for song learning.

Epigenetics

Heritable changes in gene expression caused by environmental factors without changing the DNA sequence.

DNA Methylation

Epigenetic mechanism that turns a gene OFF by tightening DNA around histones.

Histone Acetylation

Epigenetic mechanism that turns a gene ON by relaxing DNA to allow transcription.

Nurtured Rat Pups

Experience serotonin release, causing histone acetylation that turns ON glucocorticoid receptor genes (lowers adult stress).

Unnurtured Rat Pup

Suffer DNA methylation right after birth, turning OFF glucocorticoid receptor genes (causes permanent high stress).

Intergenerational Mothering Style

Poor maternal care methylates estrogen and oxytocin receptor genes, passing poor mothering behavior down epigenetically.

Epigenetics in Learning

Memory formation actively requires DNA methylation (turning specific genes off) in the hippocampus.

How do genes typically influence behavior through physical development?

They control the structures that detect and respond to stimuli, such as hormone production levels.

The banging of a door causing a dog to bark while causing a rabbit to cower is an example of a _____.

Genetic Predisposition

The field of study that examines how genes influence behavior is known as _____.

Behavioral Genetics

Besides the nucleus, where else is DNA found in animal cells?

Mitochondrion

What three components make up Chromatin?

DNA, histone proteins, and RNA.

What are variations of a specific gene called?

Alleles

How do regulatory genes influence the expression of other genes?

By producing transcription factors that alter the amount of mRNA produced.

Which specific gene is responsible for the entire courtship process in fruit flies?

The Fruitless (fru) gene.

In fruit flies, why is male courtship behavior absent in females despite both having the fru gene?

The presence of a second X chromosome causes the necessary interneurons to die during development.

Heritability

The ratio of variation caused by genetic differences to the total variability of a behavior within a population.

What is the typical heritability value for complex behavioral traits?

Below 0.5

The study of an organism's entire DNA sequence is called _____.

Genomics

What is the goal of Comparative Genomics?

To determine how behavioral traits evolved by studying genome variations between species.

How does inbreeding assist researchers in separating genetic effects from environmental effects?

It creates populations that are homozygous for most genes, minimizing genetic diversity.

What was the result of Carol Lynch's 15-generation selection study on mouse nest building?

High nest builders used 40 grams of cotton while low nest builders used only 5 grams.

What specific learning deficit is caused by the Dunce mutation in fruit flies?

An inability to learn from olfactory input and form long-term memories.

The dunce gene codes for which enzyme responsible for breaking down cAMP?

Cyclic AMP phosphodiesterase

How does a mutation in the dunce gene affect cAMP levels in fruit flies?

It causes an increase in cAMP levels, which inhibits the memory formation process.

What genetic ratio in the second generation of a hybrid cross suggests a behavior is controlled by two alleles of one gene?

A ratio of 3 dominant phenotypes to 1 recessive phenotype.

Define: Candidate Gene

A gene hypothesized to be involved in a behavior based on its known function in other species.

In the mouse hypothalamus, how does estrogen influence social bonding?

It increases the level of expression of oxytocin receptor genes.

What is the primary genetic difference causing monogamy in Prairie Voles versus non-monogamy in Meadow Voles?

Prairie Voles have a higher density of vasopressin receptors in the pleasure center of the brain.

In male Astatotilapia burtoni, what hormone/factor determines reproductive physiology and dominance status?

Gonadotropin Releasing Factor (GnRF).

Why do dominant male cichlid fish grow slower than subordinate males?

The gene for somatostatin is turned on, which inhibits growth hormone to save energy for sperm production and defense.

Under what condition does Zenk mRNA in a songbird's forebrain increase most dramatically?

When the bird is exposed to the song of an unfamiliar male of its own species.

How do 'sneaker' male Atlantic Salmon differ from migratory males in terms of brain gene activity?

Sneaker males show increased activity in genes associated with reproduction, while migratory males favor growth genes.

What percentage of genes in the brain differ in activity levels between sneaker and migratory Atlantic Salmon?

15%

In rats, what physiological change results from high levels of maternal grooming and licking?

An increase in the expression of glucocorticoid receptors in the brain, which reduces stress.

Which neurotransmitter produced in response to maternal care leads to histone acetylation of the glucocorticoid receptor gene?

Serotonin

Why do the offspring of non-nurturing mother rats remain stressed as adults?

The gene for glucocorticoid receptors is methylated (turned off) immediately after birth.

How is poor maternal behavior 'inherited' epigenetically in rats?

Methylation of estrogen receptor genes prevents proper oxytocin binding, leading to low maternal care in the next generation.

In the hippocampus, what epigenetic process appears to be required for memory formation?

Methylation