the genetic basis of behaviour Flashcards
what are some things which have been identified by genetic basis of behaviour
1) studies of naive youngsters
2)cross breeding
3)comparison of relatives
4) knock out gene experiment
5) artificial selection experiments
how does behaviour vary between California garter snakes
-2 separate populations
-one is the moist coastal areas where the snakes feat on banana slugs
-the other is the dry mountainous inland areas where they eat fish and frogs
what test was done to figure out if the two populations of California garter snakes’ diet was genetic or behavioural
-tested naive newborns with slugs and swabs of slug mucous
-if it was genetics, then the snakes would eat them
-70% of coastal snakes ate 8/10 of the slugs
-80% of inland snakes ate none of the slugs
-in regards to tongue flicking, the coastal snakes would flick their tongue more in response to slug mucus
single gene effects: rover and sitter behaviour in drosophila larvae
-sitter larvae move little when foraging
-rover larvae move around a lot when foraging
-rover is the dominant gene
comparison of relatives as a method of studying heredity of behaviour
-full siblings share 0.5 of their genes
-if only one parent in common then 0.25 of their genes are shared
-full siblings therefore more likely to share similar behaviour than half siblings
twins in regards to behaviour
-dizygotic (two eggs) share 0.5 of their genes, like regular siblings
-monozygotic (one egg) share 100% of their genes with one another and hence more similar than dizygotic
identical twins reared together
-parents tend to treat monozygotic twins more similarly e.g. dress the same
-similarities of relatives can occur due to similar environment
-to test this we can compare individuals raised together and then apart to see if its genetics or environmental
twins reared apart
-jack and oskar
-jack raised by jewish father in Caribbean
-oskar raised by catholic grandmother in nazi Germany
-both still looked very similar even though they were raised separately
-this included the same moustache, the liking of sweet liqueurs, read magazines back to front-end dipped buttered toast in their coffee, had highly similar speech
-not a happy reunion for political reasons
comparison of behaviour of relatives raised together or apart
-adopted children resemble adopted parents less
-siblings adopted separately have less spatial ability correlation then those adopted together
-genes underline spatial behaviour
knock-out gene experiment
-method of studying the genetic basis of behaviour
-inactivation of a known gene to determine its effects on development
-all subjects are genetically identical
-inactivate one gene to see what happens to the behaviour
-example: wild type female mouse with 2 functioning fosB gene- mouse crouches over her children to protect them and allows her to nurse
-mutant mouse with inactivated fosB gene ignore their newborns and they scatter as they can’t initiate biochemical series leading to abnormal behaviour
testing whether nest building behaviour can evolve using artificial selection
-the amount of cotton that mice collect varies for nests
-experimenter carol Lynch wanted to know if it was genetic or environmental
-she set up a high line, a low line and a control
-high line consisted of those who selected the most cotton
-low line consisted of those who collected the leats amount if cotton
-in high line, only the high flyers breaded, in the low one, only the lazy ones were bread
-experiment showed that: behavioural differences between individuals can be caused by genetic differences, and that genetic variation in besting behaviour at the start of the experiment allowed the population ti evolved in lab in response to artificial selection
what conditions need to be present for selection for a trait to lead to an evolutionary response
variation In the trait needs to be genetic
twin rates in islands and mainlands
-high twinning rates in islands and low in mainlands as island have predictable foods where in mainland’s there are lots of famines
