Final answer:
Alcohol use disorder is associated with Alcohol dehydrogenase 2 and Unknown Protein genes. Tobacco dependence is influenced by genetic factors involved in neurotransmitter metabolism.
Step-by-step explanation:
The two genes that are commonly associated with alcohol use disorder are Alcohol dehydrogenase 2 and Unknown Protein. Alcohol dehydrogenase 2 is an enzyme that metabolizes alcohol in the body, and variations in this gene can affect how efficiently alcohol is broken down, increasing the risk of alcohol use disorder. The other gene, the Unknown Protein, suggests that there are likely other genetic factors at play in the development of alcohol use disorder that are not yet fully understood.
As for tobacco dependence, there are no specific genes that have been identified as directly causing this disorder. However, studies have shown that there are genetic factors that can increase the vulnerability to nicotine addiction. For example, variations in genes involved in neurotransmitter metabolism, such as the dopamine receptor gene, have been associated with a higher susceptibility to nicotine dependence.