Genes And Behaviour Flashcards
Behaviour (phenotype) is a mix of…
… nature (genes) and nurture (environment) - influence of both vary depending on the trait
Evidence for genetic influence on behavior…
- closely related species often differ in their behavior
- behavior can be artificially selected for
- Ability to learn has a genetic basis too
- Some complex behaviours have simple genetic control
closely related species often differ in their behaviour…
… therefore in a constant environment differences must be due to genes (e.g. different species of baboons exhibit different herding behaviour)
behavior can be artificially selected for…
= must be a genetic basis
‣ e.g. different species of dog have been bred for different things, herding in border collies / retrieving in labradors
‣ E.g. artificially selected behaviours in drosophila in the lab (geo tactic behaviour)
Ability to learn has a genetic basis too…
‣ Selection for learning - e.g. when blow flies that are better at learning (proboscis extend reflex (used to taste) = can be conditioned to a response using sucrose) are bred together they produce quicker learners
‣ Polygenic basis (many genes contribute) for this type of learning
Some complex behaviours have simple genetic control…
‣ E.g. foraging in drosophila - 2 phenotypes found in populations (rover and sitter).
Density dependent selection: high density selects rover (finds patchy food) and low density selects sitter (doesn’t waste energy moving)
different alleles of the (for) foraging gene (which is a cGMP dependent protein kinase) determine if drosophila is a rover or sitter
E.g. Honey bee workers behaviour are influenced by genes…
- there are two types of workers: nurses and foragers - usually the young are nurses and as the get older they become forgers
- experiments found that foragers have a higher expression of (for) foraging gene than the nurses - it is not associated with the age as the age was controlled
- if you express the gene more highly in nurses they are more likely to become foragers
- also protein kinase G activity was increased using chemicals - influenced whether they became foragers or not = foraging increases with increased conc. of cGMP
vole mating behviour is controlled by genes -
avpr1a (arginine vasopressin receptor 1a) controls vole mating behaviour…
- prairie voles - monogamous males (stay with female)
- Meadow voles - promiscuous makes (has many mates)
- Found no difference in the sequence of the receptor gene but did find that meadow voles had small micro satellites in the promoter region whilst prairie had large micro satellites in the promoter region
- Microsatellite length affected the localisation of expression of the receptor avpr1a in the brain …But found that monogamy isn’t controlled by a single gene
Mice - genetic basis of parental care:
• mice cross fostered (raised with parents of different type of parental care than their own parent) acted the same as they would depending on their genetics (didn’t act like foster parent)
study found that..
- Large heritable differences in parental care
- Polygenic control = many genes involved
- Sex specific differences (some genetic regions are only important in one sex) = Differences between males and females in their genetic control
- Some loci underpin a range of behaviours, others only specific behaviours
twin studies -
compare monozygotic (identical) and dizygotic (non-identical)
see if totally genetic or if environment influences
Hypothesis: identical twins more alike in trait of interest (have higher concordance) than non-identical twins because of greater genetic similarity
Heritability =
- the proportion of phenotypic variance attributable to genetic variance
- the extent to which genetic individual differences contribute to individual differences in observed behaviour (or phenotypic individual differences)
