Epigenetics not only may create transmissible memories to biological offspring but also can alter the way the genes themselves are expressed. NIDA Notes recently reported on studies by Dr. Fair M. Vassoler and colleagues at the University of Pennsylvania and Dr. Ghazaleh Sadri-Vakili at Massachusetts General Hospital. Researchers found that male rats’ cocaine exposure affects their offspring’s drug responses. “The 'sires’ cocaine exposure induced epigenetic alterations to one or more of their genes, and the sires transmitted the alterations to their offspring via their sperm. Epigenetic alterations change the expression of a gene without changing the underlying DNA sequence. The gene produces the same protein as it did before alteration, but in greater or lesser quantities than before.” (Source)

Studies at UC San Francisco: Addiction is caused by more than the pharmacological effects of a given drug, Drug addiction is a life-long disease. Although drug-taking behaviors may be absent, the ‘memory’ makes relapse not only possible but likely. (Science News. Cocaine Addiction Linked To Voluntary Drug Use And Cellular Memory, Study Shows. 2008. Article)