Lab mice trained to fear a particular smell can transfer the impulse to their unborn sons and grandsons through a mechanism in their sperm, a study reveals.
The research claims to provide evidence for the concept of animals “inheriting” a memory of their ancestors’ traumas, and responding as if they had lived the events themselves.
It is the latest find in the study of epigenetics, in which environmental factors are said to cause genes to start behaving differently without any change to their underlying DNA encoding.
"Knowing how ancestral experiences influence descendant generations will allow us to understand more about the development of neuropsychiatric disorders that have a transgenerational basis," says study co-author Brian Dias of the Emory University School of Medicine in Atlanta, Georgia.
And it may one day lead to therapies that can soften the memory “inheritance”.
For the study, Dias and co-author Kerry Ressler trained mice, using foot shocks, to fear an odour that resembles cherry blossoms.
Later, they tested the extent to which the animals’ offspring startled when exposed to the same smell. The younger generation had not even been conceived when their fathers underwent the training, and had never smelt the odour before the experiment.
The offspring of trained mice were “able to detect and respond to far less amounts of odour… suggesting they are more sensitive” to it, says Ressler co-author of the study published in the journal Nature Neuroscience.
They did not react the same way to other odours, and compared to the offspring of non-trained mice, their reaction to the cherry blossom whiff was about 200 percent stronger, he says.
The scientists then looked at a gene (M71) that governs the functioning of an odour receptor in the nose that responds specifically to the cherry blossom smell.
The gene, inherited through the sperm of trained mice, had undergone no change to its DNA encoding, the team found.
But the gene did carry epigenetic marks that could alter its behaviour and cause it to be “expressed more” in descendants, says Dias.
This in turn caused a physical change in the brains of the trained mice, their sons and grandsons, who all had a larger glomerulus - a section in the olfactory (smell) unit of the brain.
"This happens because there are more M71 neurons in the nose sending more axons" into the brain, says Dias.
Similar changes in the brain were seen even in offspring conceived with artificial insemination from the sperm of cherry blossom-fearing fathers.
The sons of trained mouse fathers also had the altered gene expression in their sperm.
"Such information transfer would be an efficient way for parents to ‘inform’ their offspring about the importance of specific environmental features that they are likely to encounter in their future environments," says Ressler.
Happening in humans?
Commenting on the findings, British geneticist Marcus Pembrey says they could be useful in the study of phobias, anxiety and post-traumatic stress disorders.
"It is high time public health researchers took human transgenerational responses seriously," he said in a statement issued by the Science Media Centre.
"I suspect we will not understand the rise in neuropsychiatric disorders or obesity, diabetes and metabolic disruptions generally without taking a multigenerational approach."
Wolf Reik, epigenetics head at the Babraham Institute in England, says such results were “encouraging” as they suggested that transgenerational inheritance does exist, but cannot yet be extrapolated to humans.
"NO MORE" from the SVU Squad (These pictures are not mine. Creds to NOMORE.ORG )
Literally the best.
:3 Just love this so much.
Australian Musician Sings Through Entire Pokédex - Every Single One!
Musician Adrian Khoo has put together a vital song for budding Pokémon trainers. The song, which lasts for over eight minutes, took Adrian about three weeks to learn: “I knew it pretty well after a week or so, but would hesitate or stumble here and there. I wanted to rehearse it to the point where I could do it all in one take. So I spaced it out – reciting it to myself on the way to and from work.” Credit: Adrian Khoo
Rescue Ink is a non-profit organization that exists for the advocacy and protection of all animals. Based in New York, the team is compromised of a group of bikers along with an amazing group of volunteers including local police, private investigators, and lawyers. Rescue Ink is all about zero tolerance when it comes to animal abuse – and they’re not afraid to get a little in-your-face to prove it. This group of seemingly tough guys have a soft spot for all creatures and will stop at nothing, within the bounds of the law, to save animals from dire and desperate situations; they rescue fighting dogs, confront animal abusers, work to find abandoned and neglected animals loving homes, and investigate stolen animals.
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Give me thigh high stockings, intense hardware, an alter ego and i’m yours.