Early Life Experiences Influence DNA in the Adult Brain

Source: Salk Institute

Summary: A new study suggests an intriguing connection between nature versus nurture. Researchers reported that the type of mothering a female mouse provides her pups actually changes their DNA.

For at least a decade, scientists have known that most cells in the mammalian brain undergo changes to their DNA that make each neuron, for example, slightly different from its neighbor. Some of these changes are caused by “jumpinggenes, officially known as long interspersed nuclear elements (LINEs) that move from one spot in the genome to another. Previously it was discovered that a jumping gene called L1, which was already known to copy and paste itself into new places in the genome, could jump in developing neuronal brain cells. Researchers in a new study reported that the type of mothering a female mouse provides her pups actually changes their DNA, the connection between nature and nurture. The study findings were published in the journal Science.

Hippocampus located inside brain

Pictured are cells in the mouse hippocampus (whose nuclei are stained blue) that underwent mobilization of the L1 gene (green). Credit: Salk Institute

To find out, the research team began by observing natural variations in maternal care between mice and their offspring. They then looked at DNA from the offspring’s hippocampus, which is involved in emotion, memory and some involuntary functions. They discovered a correlation between maternal care and L1 copy number: mice with attentive mothers had fewer copies of the jumping gene L1, and those with neglectful mothers had more L1 copies, and thus more genetic diversity in their brains. The researchers emphasize that at this point it’s unclear whether there are functional consequences of increased L1 elements. Future work will examine whether the mice’s performance on cognitive tests, such as remembering which path in a maze leads to a treat, can be correlated with the number of L1 genes.

Prof. Rusty Gage said, “We are taught that our DNA is something stable and unchanging which makes us who we are, but in reality it’s much more dynamic”, “It turns out there are genes in your cells that are capable of copying themselves and moving around, which means that, in some ways, your DNA does change.”

More Information: T.A. Bedrosian et al, “Early life experience drives structural variation of neural genomes in mice”, Science (2018). science.sciencemag.org/cgi/doi … 1126/science.aah3378

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