Even before conception, a father who chronically drinks to excess can shape his son’s vulnerability to alcohol use disorders, according to a new study with mice.
Published in the journal PLOS ONE, the research shows that male mice that were chronically exposed to alcohol before breeding had male offspring that were less likely to consume alcohol and were more sensitive to its effects.
The findings provide new insight into inheritance and development of drinking behaviors, researchers say.
Previous human studies indicate that alcoholism can run in families, particularly father to son, but to date only a few gene variants have been associated with Alcohol Use Disorder and they account for only a small fraction of the risk of inheriting the problem, says senior investigator Gregg E. Homanics, professor of anesthesiology and pharmacology and chemical biology at University of Pittsburgh School of Medicine.
“We examined whether a father’s exposure to alcohol could alter expression of the genes he passed down to his children,” Homanics says. “Rather than mutation of the genetic sequence, environmental factors might lead to changes that modify the activity of a gene, which is called epigenetics.
“Our mouse study shows that it is possible for alcohol to modify the dad’s otherwise normal genes and influence consumption in his sons, but surprisingly not his daughters.”
No enhanced taste for alcohol
For the study, he and lead author Andrey Finegersh, a PhD student in the pharmacology and chemical biology department graduate program, chronically exposed male mice over five weeks to intermittent ethanol vapor, leading to blood alcohol levels slightly higher than the legal limit for human drivers. Then, they mated them with females who had not been exposed to alcohol.
Compared to those of ethanol-free sires, adult male offspring of ethanol-exposed mice consumed less alcohol when it was made available and were less likely to choose to drink it over water. Also, they were more susceptible to alcohol effects on motor control and reduction of anxiety.
“We suspected that the offspring of alcohol-exposed sires would have an enhanced taste for alcohol, which seems to be the pattern for humans,” Finegersh says. “Whether the unexpected reduction in alcohol drinking that was observed is due to differences between species or the specific drinking model that was tested is unclear.”
The researchers plan to examine other drinking models such as binge drinking, identify how alcohol modifies the genes, and explore why female offspring appear unaffected.
The National Institute on Alcohol Abuse and Alcoholism, part of the National Institutes of Health, funded the study.
Source: University of Pittsburgh