Genetic Determinants of Behaviour

Question 1

Do genes or the environment play more of a role in behaviour?

Answer 1

Both - they interact and both influence variation

Question 2

What is an example of natural variants?

Answer 2

Drosophila rover and sitter alleles - rovers disperse across food patches and sitters stay in one

Question 3

Why might the rover-sitter polymorphism persist?

Answer 3

Frequency-dependent selection where fitness changes based on food patch availability

Question 4

What happens when there is a high abundance of food?

Answer 4

Higher reproductive success of sitters

Question 5

What happens when there is a low abundance of food?

Answer 5

Higher reproductive success of sitters

Question 6

Why do population differences cause different behaviours?

Answer 6

Ecologically discrete populations differ in both environment and genetics (allele frequencies)

Question 7

Give an example where different populations have displayed different behaviours

Answer 7

Shoaling behaviour in guppies - guppies that are more used to being at risk of predation shoal more tightly in lab standardised conditions when alarmed

Question 8

What are innate behaviours?

Answer 8

Behaviours that are performed from birth - they can be adjusted by learning through life

Question 9

Give an example of innate behaviours

Answer 9

Laughing gull (Larus atricilla) chicks peck parents beak to be fed from birth but their accuracy improves with age (learned)

Question 10

Give an example of cross fostering behaviours

Answer 10

Cross fostered blue and great tits (child swap) - song repertoire large with aspects from birth parents and foster parents

Question 11

How is heritability used to figure out the determinants of resemblance?

Answer 11

Use known relationships and measure resemblance - if variation between full siblings, siblings and unrelated individuals then large genetic component; if variation is similar then large environmental component

Question 12

Give an example of heritability experiments

Answer 12

Ballooning spiders - fly using webs and wind - enabled by genetics but how often they balloon depends on parents

Question 13

What are isolines?

Answer 13

Make clones by inbreeding lines for many generations until individuals from that line are pretty much identical

Question 14

Give an example of when isolines have been used to investigate the determinants for behaviour

Answer 14

200 inbred lines of Drosophila, fully sequenced and then tested for traits and SNPs (increased gene component = same behaviour; increased environment component = different behaviour)

Question 15

How is artificial selection used to test for determinants of behaviour?

Answer 15

For heritable behaviour, impose a selection pressure (pick the individuals that get to mate) and measure how behaviour changes in subsequent generations

Question 16

Give an example of when artificial selection has been used to investigate the determinants for behaviour

Answer 16

Flight capacity in beet army worm moths - long fliers breed with long fliers and produce offspring who fly for longer

Question 17

How does gene expression help uncover the determinants for behaviour?

Answer 17

Measure gene expression using RNAseq (whole transcriptome) or qRT-PCR (single gene): an increase or decrease in gene expression.

Question 18

Give an example of when gene expression has been used to investigate determinants for behaviour

Answer 18

Burying beetles and parenting - sequence the transcriptome and analyse differences between parental and bi-parental beetles (867 genes differentially expressed)

Question 19

How do classical mutants help uncover the determinants of behaviour?

Answer 19

Induce mutations by x-ray or chemical mutagenesis

Question 20

Give an example of when classical mutants have been used to investigate the determinants of behaviour

Answer 20

Fruitless and male courtship in Drosophila - induce males with fruitless gene so that can’t distinguish male and females so flies mate indiscriminately (genetic component).

Question 21

What is RNAinterference?

Answer 21

Knock down gene expression by co-opting the cell’s antiviral machinery to cleve double stranded DNA

Question 22

Describe the in vitro process of RNAi

Answer 22

1. Selection of target gene for gene silencing
2. Designing si/shRNA specific to target gene
3. Selecting a plasmid or vector
4. Introducing the dsRNA to cells
5. Gene expression assay

Question 23

Give an example of when RNAi has been used to investigate the determinants of behaviour

Answer 23

Trp-A1 gene and heat avoidance in flour beetle - Arena 50% good temperature, 50% too warm; non mutants go to good side; mutants 50/50 don’t recognise the difference - gene associated with temperature recognition

Question 24

What is phenotypic plasticity?

Answer 24

Where a genotype can make many phenotypes

Question 25

Give an example of when phenotypic plasticity has been used to investigate the determinants for behaviour

Answer 25

Drosophila learning and memory - short, medium and long term memory and anaesthesia-resistant memory

Question 26

What are the three mutant or knockdown flies training tests?

Answer 26

1. T-maze odour assay
2. Visual learning
3. Complex courtship assay

Question 27

What is the T-maze odour assay?

Answer 27

Reward in one arm, shock in the other - in future flies avoid the arm with the shock

Question 28

Give an example of visual learning in flies

Answer 28

Comfortable cold patch marked with dot, when dot is moved to non cold dot, the flies still go to the dot

Question 29

What is the complex courtship assay?

Answer 29

Males more attracted to females who haven’t mated, because they have more chance of reproductive success (selective advantage)

Question 30

What is epigenetics?

Answer 30

Non-coding modifications of DNA could link environmental cues with behaviour, by making genes more or less available for expression

Question 31

Give two examples of epigenetics

Answer 31

DNA methylation and histone modification

Question 32

Give an example of when epigenetics has been used to investigate the determinants for behaviour

Answer 32

Maternal care by rats - only parents (mothers) change in methylation of BDNF gene across generations - poor treatment leads to poor treatment of offspring

Question 33

Describe the epigenetic control of caste differentiation in carpenter ants

Answer 33

Soldier ants vs forager ants - knocking down Rpd3 alters histone acetylation and makes majors more likely to forage

Question 34

How does behaviour drive or reinforce speciation

Answer 34

Assortative mating of Heliconius - QTL mapping identifies 3 loci which drive male courtship preference