Lecture 2: Behavior Genetics, Evolution, and Domestication

What is behavior genetics?

Study of how genetic and environmental factors influence behaviors

What is heritability?

Proportion of variation in behavior that is attributed to genetic differences among individuals

What is gene-environment interaction?

How different environments can affect the expression of genetic traits and vice versa

What is quantitative trait loci (QTL):

Specific regions of the genome that are associated with particular behavioral traits

What are the 10 dog breed genetic lineages?

• Pointer Spaniel: Cocker Spaniel

• Herder: Border Collie

• Sled dog: Siberian Husky

• Terrier: Jack Russel

• Scent hound: Bloodhound

• Retriever: Golden Retriever

• Asian Spitz: Shiba Inu

• Sighthound: Whippet

• African and Middle Eastern: Rhodesian Ridgeback

• Dingo: Dingo

What are the unique behaviors of Pointer-Spaniel Lineage?

• Decreased stranger-directed aggression and decreased dog-directed aggression

• Used as gun dogs

• Examples: Cocker Spaniel, English Springer Spaniel, Irish Setter, German Shorthaired Pointer, Vizsla

What are the unique behaviors of Herder Lineage?

• Very strong positive correlation with non-social fear

• Used as protecting or moving livestock

• Example: Border Collie, Shetland Sheepdog, Pembroke Welsh Corgi, Australian Cattle Dog

What are the unique behaviors of Sled Dog Lineage?

• Moderate predatory instinct and low trainability

• Used for carrying loads

• Example: Alaskan Malamute, Siberian Husky

What are the unique behaviors of Terrier Lineage?

• Positive correlations with dog-directed fear, aggression, rivalry, non-social fear, and predatory drive

• Used for vermin control

• Example: Jack Russell, Wire Fox Terrier, Cairn Terrier, Irish Terrier, Soft Coated Wheaten Terrier, Airedale Terrier

What are the unique behaviors of Scent Hound Lineage?

• Strong negative correlation with trainability. Positive correlations with non-social fear and dog rivalry (familiar dog aggression)

• Used to track game by scent

• Examples: Bloodhound, English Foxhound, Petit Basset

  Griffon Vendeen

What are the unique behaviors of Retriever Lineage?

• Low predatory drive

• Gun dogs and water dogs for retrieving game

• Example: Labrador Retriever, Golden Retriever, Chesapeake Bay Retriever

What are the unique behaviors of Asian Spitz Lineage?

• Positive correlation with owner-directed aggression and negative correlation with trainability

• Used for hunting and guardian dogs

• Example: Chow Chow, Akita, Tibetan Mastiff, Shiba Inu

What are the unique behaviors of Sighthound Lineage?

• Lower energy and excitability

• Used for hunting because of speed and sight

• Example: Irish Wolfhound, Whippet, Greyhound, Borzoi

What are the African and Middle Eastern Lineage breeds?

Saluki, Rhodesian Ridgeback

What are the Dingo Lineage breeds?

Dingo, New Guinea Singing Dogs, Highland Wild Dog

What was the focus of Carol B. Lynch’s 1980 study?

Focus on the heritability and genetic architecture of nest-building behavior in house mice

What was the selection experiments in Carol B. Lynch's 1980 study?

Mice were bred for high and low nest-building behavior over several generation

What was the genetic correlations in Carol B. Lynch's 1980 study?

The nest-building behavior is positively correlated with other traits such as body temperature regulation and reproductive success. Mice that built larger nests tended to have better thermoregulation and higher reproductive success

What was the dominance and epistasis in Carol B. Lynch's 1980 study?

Dominance and epistatic interactions (interactions between different genes) in determining nest-building behavior

What was the adaptive significance in Carol B. Lynch's 1980 study?

Mice that built better nests were more likely to survive and reproduce successfully in colder condition

What is evolution?

Process by which species change over time through natural selection, genetic drift, mutation, and gene flow

What is natural selection?

The process where individuals with advantageous traits are more likely to survive and reproduce, passing those traits to the next generation; Loss of genetic infromation

What is adaptation?

Traits that enhance an organism's ability to survive and reproduce in a particular environment

What is speciation?

The formation of new and distinct species through evolutionary processes

What is domestication?

Process by which humans have modified wild animals and plants for their benefit through selective breeding

What is genetic (artificial) selection?

Humans select for traits such as tameness, productivity, and adaptability to human environment

What is domestication syndrome?

A set of traits commonly seen in domesticated animals, such as reduced aggression, increased sociability, and physical changes like floppy ears and shorter limbs

What is the farm-fox experiment?

A study by Dmitry Belyaev that demonstrated how selective breeding for tameness in foxes led to rapid changes in behavior and physical trait

What happens with domestication syndrome?

• Increased Tameness and Docili

• Prolonged Juvenile Behavior

• Floppy ears

• Coat color Variations

• Reduced Brain SIze

• CHnages in Craniofacial Morphology

What is the Farm-Fox experiment?

Selectively breeding silver foxes (a melanistic form of the red fox) for tameness for domestication

What are innate behaviors?

Behaviors that are hard-wired into an animal's genetic code and are typically performed without prior experience or learning; reflexes and fixed action pattern (e.g., a spider spinning a web or a bird building a nest)

What is heritability?

Certain behaviors can be passed down from one generation to the next through genes; maze-running ability (mice) and temperament (dogs) can be selectively bred

What are genetic variations?

Differences in specific genes can lead to variations in behavior; variations in the oxytocin receptor gene in dogs have been linked to differences in social bonding behaviors

What are learning and experience?

Animals can modify their behavior based on experiences; a dog can learn to sit on command through training, and birds can learn to avoid certain foods that made them sick in the past

What are developmental environments?

The conditions an animal experiences during its development, such as maternal care and early social interactions, can shape its behavior later in life

What are gene-environment interactions?

The expression of genetic traits can be influenced by environmental factors; a genetically timid animal might become more confident if raised in a nurturing environment

What are epigenetics?

Environmental factors can cause changes in gene expression without altering the DNA sequence; these changes can affect behavior and can sometimes be passed on to future generations

What are maze-bright and maze-dull rats?

Rats bred for their ability to navigate a maze; over generations: "maze-bright" rats vs "maze-dull" rats

What are fearful behaviors in dogs?

Certain breeds are more prone to fearful behaviors due to genetic factors; however, the environment (socialization and training) can also influence these behaviors

What is gene mapping?

The process of determining the specific locations of genes on a chromosome; to understand the genetic basis of traits and diseases

What is gene linkage?

The phenomenon where genes that are located close to each other on the same chromosome tend to be inherited together (because the genes are physically linked and less likely to be separated during the process of recombination in meiosis).

What are chromosomes and genes?

Chromosomes are long strands of DNA that contain many genes; each gene occupies a specific position (locus) on a chromosome; during meiosis, homologous chromosomes (pairs of similar chromosomes) exchange segments in recombination or crossing over

What are linkage groups?

Genes that are located close to each other on the same chromosome form a linkage group; these genes are more likely to be inherited together because the probability of a crossover event separating them is low

What is epigenetics?

Study of how behaviors and environmental factors can cause changes that affect the way genes work, without altering the DNA sequence itself

What is DNA methylation?

Adding a methyl group to DNA, usually at cytosine bases; this modification can suppress gene expression by preventing the binding of transcription factors

What are histone modifications?

Histones are proteins around which DNA is wrapped; chemical modifications to histones (acetylation or methylation), can influence how tightly or loosely DNA is wound around them, thereby regulating gene expression

What is non-coding RNA?

These RNA molecules do not code for proteins but can regulate gene expression by interacting with other RNAs or DNA

What are the environmental influences of epigenetics?

• Diet

• Stress

• Toxins

What are the health implications of epigenetics?

• Cancer

• Mental health

• Developmental disorders

What is the canine epigenetic clock?

• The epigenome (the collection of chemical changes to its DNA and histone proteins) is highly predictive of chronological age

• DNA methylation profiles and chromatin accessibility as biomarkers of aging

Therapeutic interventions can help modify…

Epigenetic marks to treat disease

What are darwin’s original writings?

• The principle of variation

• The principle of genetic inheritance

• The principle of natural selection

What are genetic mutations?

Changes in the DNA sequence that can introduce new genetic variations; some mutations can be beneficial, providing new traits that can be acted upon by natural selection

What is gene flow (gene migration)?

The transfer of genetic material between populations, which can increase genetic diversity

What is genetic drift?

Random changes in the frequency of alleles (variants of a gene) in a population, which can lead to significant changes over time, especially in small populations, leading to a loss of genetic variation; population bottleneck, founder effect

What is natural selection?

Organisms with traits that are better suited to their environment tend to survive and reproduce, passing those traits to the next generation

How do you track the evolutionary history of behavior?

• Behavioral archeology

• Phylogenetic trees

What is fossil evidence?

They can provide indirect clues about behavior: track marks, nesting sites, and other

preserved characteristics can suggest how extinct animals might have behaved

What are comparative methods?

By comparing the behavior of closely related species, we can infer the likely behavior of their common ancestors: “similar behaviors in related species are likely inherited from a common ancestor”

What is phylogenetics?

Evolutionary trees (phylogenies) trace the lineage of species; by mapping behavioral traits onto these trees, we can infer when and how certain behaviors evolved

What is behavioral ecology?

The ecological and evolutionary basis for animal behavior: environmental pressures and the behavior of extinct species

What is genetic studies?

modern genetic techniques to identify genes associated with specific behaviors; comparing these genes across different species: evolutionary history of these behavior

What is a phylogenetic tree?

Diagram that represents the evolutionary relationships among various species based on their behavioral traits.

What is ritualization?

• Process by which non-signaling behaviors evolve to become communicative signals

• Involves the exaggeration, simplification, and formalization of behaviors to enhance their effectiveness as signals

• Enhances the clarity and effectiveness of communication in animals, playing a crucial role in social interactions, mating, and survival.

What is an evolutionary process in relation to ritualization?

RItualization involves the evolution of behaviors that were not originally meant for communication into signals that convey specific information (e.g., a bird's preening behavior might evolve into a courtship display)

What is stereotypy in relation to ritualization?

Ritualized behaviors become highly stereotyped, meaning they are performed in a consistent and repetitive manner. This helps reduce ambiguity and ensures the signal is clear to other animals

What are examples of ritualized behaviors?

Courtship displays, territorial displays, and threat displays. For instance, the pecking behavior of woodpeckers, which is normally used for feeding, becomes a rhythmic drumming used to communicate territory

Ritualization steps in animal behavior?

1. Clear communication

2. Reducing aggression

3. Mate assessment

4. Species recognition

What is survival?

Behaviors that help animals avoid predators, find food, and shelter are essential for survival. For example, camouflage and evasive maneuvers help animals escape predators

What is reproduction?

Behaviors related to mating and raising offspring ensure the continuation of a species. Courtship displays, nest building, and parental care are all behaviors that enhance reproductive success

What is communication?

Animals use various behaviors to communicate with each other. This can include vocalizations, body language, and chemical signals. Effective communication is vital for coordinating group activities, warning of danger, and establishing social hierarch

What is social structure?

Many animals live in social groups, and behaviors that establish and maintain social structures are important. This includes dominance hierarchies, cooperative hunting, and grooming behaviors that strengthen social bon

What is adaptation to the environemt?

Behaviors that allow animals to adapt to their environment are crucial. This includes migration to avoid harsh weather, hibernation to survive periods of food scarcity, and foraging strategies that maximize food intake

What is learning and memory?

Animals exhibit behaviors that involve learning from experiences and remembering important information. This helps them adapt to changing environments and improve their chances of survival

Domestication timeline

1. Dog: 20000

2. Sheep: 8500

3. Cat: 8500

4. Pig: 7000

5. Cow: 7000

6. Chicken: 6000

7. Horse: 3600

What impacts an animal during domestication?

• Reduced aggression and fear

• Increased sociability

• Changes in reproductive behavior

• Altered stress responses

• Retention of Juvenile traits

• Behavioral plasticity

What are Jarde Diamond’s six criteria for domestication?

1. Diet

2. Growth rate

3. Breeding in captivity

4. Temperament

5. Social structure

6. Low tendency to panic

What animals are a part of the commensal pathway?

• Dog

• Cat

• Pig

• Chicken

What animals are a part of the prey pathway?

• Goat

• Sheep

• Cattle

• Asiatic buffalo

• Alpaca

• Llama

Directed pathway

• Horse

• Camel

• Dumb

• Dromedary