Genes and Behaviour

A unit of heredity made of DNA that influences biological traits.

A biological tendency to develop a trait or behaviour.

The idea that behaviour is influenced by the interaction between genetic factors and environmental experiences.

A gene involved in the transport of serotonin.

a mutation may lead to a lower serotine transport effeiceny which may lead to consistent low mood a common behaviour of depression

neuotransmitter that infleuces mood, emotion, sleep and agression

Major depressive disorder (MDD) is a mood disoder in which characterized by persistent, intense feelings of sadness, worthlessness, and a loss of interest in activities lasting at least two weeks.

Genes may infleuce depresive behaviour

Caspi et al (2003)

to inevstigate the effect of the size of the 5-HTT gene on likeyhood of MDD

Correlational study, logitiional, quasi
opporunity sample 847 new zealanders that were a part of a cohort of participants who were part of another longitudinal study, When they were 21 using genetic testing to test for varients of the 5-HTT gene and used self-reported measures to measure the exposure to stressful life events and symptoms of depression until the age for 26
3 groups
2 long allels
1 short and 1 long allele
2 short allele

Paritcipents with one or two short alleles were more likley to develop MDD symptoms following stressful life events.
Participents with 2 long alleles were less likley to develope MDD symptoms
This suggests the short alleles is associated with reduced efficiency in serotonin transport, which may affect mood regulation.

Genes don't directly cause behvaiour but influece the likleyhood of development certain behaviours such as depressive symptoms, in response to environmental stress. Therefore, genes may affect behaviour through gene–environment interaction,