Final answer:
The likely mechanism of action of genetic influences on depression is an influence on neurobiological factors, affecting neurotransmitters and hormonal balances involved in mood and behavior.
Step-by-step explanation:
The mechanism of action through which genetic influences affect depression is primarily through an influence on neurobiological factors. Research indicates that multiple genes are associated with behavioral traits and psychological disorders such as depression and schizophrenia, impacting neurobiological pathways. These genetic impacts manifest through the modulation of neurotransmitters like serotonin and dopamine, as well as the potential dysregulation of hormones like leptin and ghrelin that are involved in energy homeostasis and appetite control. Furthermore, genetic variations can modify an individual's response to stress and their susceptibility to mental health disorders, thereby interacting with environmental factors in a complex manner.