Week 10

Question 1

Why are class Mammalia interesting?

Answer 1

Unique reproduction: obligate internal gestation + lactation + altricial –> imbalance in reproductive costs & parental investment
Often complex sociality
Highly variable lifespans
Highly variable feeding strategies
Advanced cognition
Learning & teaching
Tool use
Contains mammals

Question 2

What research topics are mammals good for?

Answer 2

Social behaviour and foraging and behaviour

Question 3

What is the classic dichotomy of nature vs nurture?

Answer 3

Nativism “innate instincts”
Independent aspects merged during ”development”
Behaviour a result/outcome
Led to eugenics

Question 4

What is the modern synthesis of nature vs nurture?

Answer 4

Developmentalist approach
Appreciating complex interactions of life stage, inherited factors and external factors
Behavioural traits part of the “nature” not outcome of it.

Question 5

What is an overview of epigenetics?

Answer 5

“epi” = above
Molecules that alter gene expression
Does not alter DNA sequence itself!

Question 6

What are types of epigenetics?

Answer 6

DNA methylation (via methyltransferase)
Histone modification (e.g. acetylation via acetyltransferase)
Noncoding RNAs

Question 7

What is the outcome of epigenetics?

Answer 7

Essential for genomic regulation
What genes, when to express, how much to!?
Changes may be caused by age, sex, diet, exercise, stress, toxins, disease, individual variation, experiences
Shown to be heritable!

Question 8

What is an example of heritable epigenetics?

Answer 8

Transgenerational epigenetic inheritance of traumatic experiences
Dutch famine small babies for generations after

Question 9

What was the sample of Dogs for experiment of Morril et al?

Answer 9

18,385 dog-owner surveys
49% purebred, 51% mixed-breed
2155 dogs genome sequenced

Question 10

What was the aim of the experiment by Morril et al?

Answer 10

Most dog breeds are within the last few centuries so not enough time for behaviours to fully set in and be distinguished for each breed

Question 11

What was done to identify loci to behavioural traits in dogs?

Answer 11

GWAS - genome wide association studies

Question 12

What were example pf genes to behaviour through GWAS by Morril et al?

Answer 12

Get stuck behind objects - Chr 6 C –> T SNP - T more likely
Human sociability - Chr 2 G - T - more social
Both correlational studies

Question 13

What was the outcome of the GWAS by Morril et al?

Answer 13

ID genes associated with behaviours, but not with specific breeds
Physical traits heavily breed-specific through GWAS (perhaps expected?!)
Age and sex biggest predictors of individual dog behaviour (of those assessed)
Overall: breed not a predictor of individual dog behaviour
Though Toy directed motor pattern was a gene link

Question 14

How many dogs were samples by Dutrow et al?

Answer 14

4061 dogs (Canis familiaris) sampled: WGS or SNP array (DNA variants)
46,000 dog-owner surveys

Question 15

What were the results of Dutrow et al relation to each other and behaviours?

Answer 15

Dog breeds bred for similar purpose eg Sheepdogs are more similar than they are to dogs bred for another purpose

Question 16

What were the results of the survey by Dutrow et al?

Answer 16

Patterns roughly line up with expected
Terriers had a strong positive correlation with predatory chasing
Bloodhounds strong negative correlation with trainability

Question 17

What were the results of the heatmap by Dutrow et al?

Answer 17

Sheepdogs has strong heat for trainability and energy/excitiblity
Terriers has strong heat for energy/excitibility and aggresion
Companion and Toy dogs have strong heat for aggresion and fear

Question 18

How did Dutrow et al map linkages between genes and behaviour?

Answer 18

Top 100 GWAS loci per each dog lineage in a map with same key as showing relation

Question 19

What is an example of the outcomes present by Dutrow et al?

Answer 19

Enriched for genes involved in motor, vision and excitability neuronal connections
Similar to genes linked to many human behavioural conditions eg ADHD
Overall genomic signal of breed-related behavioural traits identified

Question 20

Why is there a reason to be cautious about breeds and linkage to behaviour?

Answer 20

Mixed findings point to complex (& poorly understood) inherited components
Cultural, social and political implications move faster than science
UK Dangerous dog act of 1997 chapter 53 - Dog being a banned breed eg Pitbull depends on what it looks lke rather than breed or name. Dog can be taken away regardless if not acting dangerously or having been a complant

Question 21

What is an example of despotic hierarchy?

Answer 21

Meerkats (Suricatta suricatta)

Question 22

What and why has despotic hierarchy formed in meerkats?

Answer 22

Obligate cooperative breeding; subordinates help raise offspring
Limited resources & extreme environmental pressures - lives in Kalahari desert
Every individual breeding simply not sustainable

Question 23

What happens with despotic hierarchy in Meerkat?

Answer 23

Despotic matriarchal hierarchy
Eviction/ fighting of pregnant subordinates –> to force an abortion
Infanticide of subordinate offspring
Aggressive coercion to help raise offspring

Question 24

What causes aggresive female meerkat enforced social structure?

Answer 24

High in androstenedione (steroid)
Exceptionally high testosterone
Females behaviourally & physiologically masculinized

Question 25

What are the hormones difference between dominant and subordinate meerkats during pregnancy?

Answer 25

Higher levels of androgen consistantely across all of the pregnancy for dominant females compared to subordinate females

Question 26

How do androgen blockers impact meerkat society?

Answer 26

Decreases in androgen
Decrease in scent marking
Decrease in dominant beatings
Subordinate females fight for power as dominant females no longer recieves same treatment
Decrease in food stealing

Question 27

How does mother meerkats status predict offspring behaviour?

Answer 27

Hormonal exposure of foetus during pregnancy –> higher androgens at birth –> inheritance of dominant behavioural traits –> evolutionary competitive edge!

Question 28

What is the overview of Toxoplasma gondii?

Answer 28

Lifecycle includes “accidental” or intermediate hosts
Range of disease symptoms termed toxoplasmosis in humans or livestock
Cysts can remain in the brain of hosts for life –> chronic infection

Question 29

What is the lifecycle of Toxoplasma gondii?

Answer 29

Rodant - intermediate host
Cat - definitive host
Toxoplasma shed by cat for <2 weeks after infection
Oocysts move on to next intermidiate host –> can get to humans either directly or through an intermediate

Question 30

What are examples of behavioural changes in rodents by Toxoplasma gondii?

Answer 30

Greater attraction to cat urine odour
Greater preference for large and easy rewards
Greater risk takers ie less aversion to novel stimuli and more likely to take risks for risky rewards
Greater attraction for receptive females

Question 31

How goes Toxoplasma gondii impact neurotransmitter and epigenetics?

Answer 31

T. gondii genome contains dopamine gene homologs
Increased availability of dopamine in infected host brain
Arginine vasopressin synthesis increase in medial amygdala
Both related to motivation & sexual pheromones
Rodents more impulsive, reckless –> reduced fear

Question 32

What hormonal shifts in hosts caused by Toxoplasma gondii?

Answer 32

T. gondii can cross barriers into eyes, brain & testes
Increases testosterone production in male rats, dogs, rabbits
Testosterone reduces anxiety & fear & increases male attractiveness
Crucial for T. gondii – castrated males do not show behaviour changes!

Question 33

What neuroinflammation in host brain changes caused by Toxoplasma gondii?

Answer 33

Encystment in host brain causes immunological responses
Anti-inflammatory drugs reduce host behavioural effects of infection
Extent of encystment and chronic infection impacts behaviour changes

Question 34

What is an overview of Toxoplasmosis in humans?

Answer 34

Most infectious parasites –> ~50% of population
Association between suicide attempts and infection
Link to explosive road rage