Lecture 1 - Behavioural genetics Flashcards
What are the steps in natural selection?
- Variation between individuals
- Variation is heritable
- Individuals less well adapted are less likely to survive - (Survival of the fittest)
What did Cosmides and Tooby (1992) propose?
Likened the mind to a Swiss army knife - crammed with specific tools for specific tasks
Who discovered the double helix structure of DNA?
Crick and Watson
Why is it important that DNA has a double helix structure?
Enables the replication of the DNA strands
What process allows DNA to become mRNA?
Transcription
Not all DNA is transcribed. The parts that are are called…
Exons
Who discovered the laws of genetic inheritance?
Gregor Mendel, 1850-1860
What does Genotype mean?
Refers to the set of genes an organism possesses
What does Phenotype mean?
Refers to the appearance of an organism that results from the interaction between the genes and the environment
What does Homozygous mean?
2 Identical alleles
What does heterozygous mean?
2 different alleles
What does polymorphism mean?
Common different forms of a gene
What does the process of Knockout Technology involve?
Gene removed or inactivated so not expressed
- Useful to determine function of different genes
What are the symptoms of Huntingdon’s disease?
- chorea
- cognitive deficits
- psychiatric deficits
What is Huntington’s disease?
The degeneration of neutrons in the caudate nucleus and putamen
What are the symptoms of Tay-Sachs disease?
- Seizures
- blindness
- degeneration or motor and mental abilities
- death after a few years
What is Tay-Sachs disease?
Caused by a dysfunctional protein that acts as an enzyme, known as HexA.
Leads to a failure in the breaking down of lipids in the brain
What is heritability?
An estimate of the proportion of variability that occurred in a particular trait as a result of genetic variation
What is epigenetics?
The idea that the external environment can modify gene expression by influencing the DNA function
Tryon’s (1934) study
Trained rats on a maze
- Interbred rates that made the fewest mistakes, and those that made the most mistakes
= Bright rats, easily solved maze
=Dull rats - found it harder
Eventually the overlap between scores was removed as the bright rats became Bettie and the dull rats worse
–> shows that some elements of intelligence are likely to be genetic (polygenic)
How did Searle’s (1949) findings contradict Tryon’s?
found that this selective breeding (rats) affected up to 30 traits bedsides intelligence
- bright rats tended to be less emotional
What did Cooper and Zubeck (1958) find in relation to Tyron’s study?
- Environment in which the rats were raised had an influence on their level of learning
- in a restricted environment, both sets of rats made a large number of errors
- in an enriched environment, both sets of rats made considerably less mistakes
- Interaction of environment and genes
Plomin and DeFries (1998)
Compared twins on a range of cognitive tasks
- On all tasks, the twins ability was more similar if they were monozygotic compared with those that were dizygotic
