Maternal Infection in Mice Leads to Three Generations of Behavioral Changes

October 30, 2015 · Posted in Risk Factors 

infection in mouse leads to behavioral changes in later generations

Epigenetics is the process by which environmental factors affect the way a person’s genes are transcribed. These changes, which may include the addition or subtraction of methyl groups from DNA, change the DNA’s structure (how tightly it is wound around the histones that give it shape) but not its sequence. These structural changes, which affect how easily the DNA is transcribed, can then be passed on to future generations. A new study by Ulrike Stadlbauer and colleagues presented at the Society of Biological Psychiatry explored a particular pathway by which an infection in a pregnant mouse can lead to behavioral changes in three following generations of mice.

Pregnant mice were given injections that produced an infection. A first generation of offspring were interbred to create a second generation of offspring, and these were interbred to create a third generation of offspring. The first generation of offspring had epigenetic changes in methylation and hydroxymethylation to promoter regions of two enzymes that regulate synthesis of the neurotransmitter GABA, and these epigenetic changes were associated with reduced mRNA expression of these two genes.

All three generations of offspring had deficits in social interaction, short-term memory, and cued fear conditioning. Interestingly, the second and third offspring generations also exhibited depression-like behavior that had not been present in the original mothers or the first generation of offspring.

Editor’s Note: This is another fascinating demonstration of how environmental occurrences, which can include stressors, exposure to drugs, and now immune challenges, can have effects across generations, likely through epigenetic changes that persist in ova or sperm. Amazingly, it turns out that the environment can change traits in future generations, not by inducing changes to gene sequences, but through epigenetic changes to the structure of DNA or histones that persist across generations.


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