Page URL: https://www.bionews.org.uk/page_94573

Trauma can be passed down through sperm

28 April 2014
Appeared in BioNews 751

Stress in early life can alter the production of small sections of the genetic material RNA in the sperm of mice, affecting behaviour not only in the mice themselves but also in their offspring, research suggests.

Researchers at the University of Zurich 'traumatised' male mice by separating them from the mother at unpredictable times in the first two weeks of life. When these young mice because adults, they were less hesitant to enter open spaces and brightly lit areas than mice that had not been separated from their mothers.

These behavioural changes were also present in the mice's offspring, which also displayed alterations in metabolism, and in their offspring's offspring.

'We were able to demonstrate for the first time that traumatic experiences affect metabolism in the long-term and that these changes are hereditary', said Professor Isabelle Mansuy, who led the study.

'What it's doing is building on the notion that dad's contribution is actually more than just his genes when he fertilises the oocyte,' said Professor Stephen Krawetz from Wayne State University, who studies RNA in sperm but was not involved in the study. '[It] really adds a new dimension in terms of what impact dad can have'.

The question of how epigenetic changes are passed on through sperm continues to be a matter of debate, with one proposed mechanism centering on alterations in the levels of small non-coding RNAs called micro RNAs (miRNAs) in sperm. These miRNAs turn down the expression of specific target genes, potentially causing long-lasting changes in gene expression.

In this latest study, researchers found increases in several miRNAs in the sperm of traumatised mice. The same changes were also observed in the hippocampus (the area of the brain usually associated with stress sensing) in their offspring.

To see whether these alterations could be responsible for the abnormal behaviour in the next generation, the scientists isolated RNA from the sperm of traumatised mice and injected it into an egg that had already been fertilised, excluding any effects due to changes to the DNA of the sperm.

They found that the resulting mice developed the same behavioural and metabolic abnormalities as the natural offspring of the traumatised mice, suggesting that these effects were transmitted through miRNA in the sperm.

'That was the best and most causal evidence we could provide', said Professor Mansuy.

Nonetheless, the authors admit that many questions are still to be answered. It is not known how stress in early life can induce these miRNA changes in sperm, or how these changes cause the behavioural effects in the offspring.

Dr Minoo Rassoulzadegan, a geneticist at the University of Nice who advised the researchers but was not herself an author, commented: 'This is the question for the future, to find out what [the RNA] is doing to the genome'.

SOURCES & REFERENCES
Can mental trauma be passed on through sperm?
NHS Choices |  24 April 2014
Implication of sperm RNAs in transgenerational inheritance of the effects of early trauma in mice
Nature Neuroscience |  13 April 2014
Sperm RNA carries marks of trauma
Nature News |  14 April 2014
Traces of Trauma in Sperm RNA
The Scientist |  13 April 2014
Trauma can be inherited from parents
Daily Telegraph |  14 April 2014
RELATED ARTICLES FROM THE BIONEWS ARCHIVE
30 May 2017 - by Dr Ashley Cartwright 
Mouse sperm stored aboard the International Space Station for nine months has been used to produce healthy pups back on Earth...
2 November 2015 - by Dr Jess Buxton 
A recent study suggests that embryonic gene activity may be altered by factors present in the womb even before implantation. This finding triggered a somewhat misleading newspaper article entitled 'Infertile mums "pass on DNA"', which claimed the research means recipients of donor eggs are passing on their own DNA to their child. This isn't the case...
1 September 2015 - by Professor Marcus Pembrey 
Human studies of transgenerational responses are fraught with difficulties, but definitely worth pursuing...
1 September 2015 - by Antony Blackburn-Starza 
Genetic expression adjustments linked to stress and trauma may be inherited by children, a study has claimed. The findings may support the view that the effects of life experiences on gene expression could be passed on to the next generation...
8 June 2015 - by Dr Julia Hill 
Scientists have discovered that changes to DNA which occur during a person’s lifetime can be passed on to future generations...
7 April 2014 - by Dr Kimberley Bryon-Dodd 
Smoking before puberty may lead to men fathering fatter sons, suggesting that lifestyle factors can have adverse impacts on the next generation, a study has found...
2 December 2013 - by Siobhan Chan 
Mice that were conditioned to fear a specific smell passed down this fear to their offspring, suggesting that traumatic events can affect gene expression...
15 July 2013 - by Emily Hoggar 
Exercise directly affects which genes are expressed or silenced, causing fat cells to function differently, according to a study in PLOS Genetics...
8 November 2010 - by Chris Chatterton 
New research suggests that the impact of stress may be passed on from one generation to the next, and that psychiatric illness may have some degree of 'epigenetic heritability'....
HAVE YOUR SAY
Log in to add a Comment.

By posting a comment you agree to abide by the BioNews terms and conditions


Syndicate this story - click here to enquire about using this story.