Submitted by St George’s Dragon
It has been a mystery up to now how things experienced during the lifetime of an animal (and that includes humans) can affect their descendants. Traditional biological theory says that lifetime events cannot have an impact on future generations as genetic inheritance relies only on the mixing of genes from the parents – and those genes are fixed and unaffected by events.
There have been clues from scientific studies in the past which show that the frequency of some illnesses such as schizophrenia, bipolar disorder and obesity are affected by the experiences of previous generations. For example, the children of women who were starving during pregnancy in the Second World War grew up with an increased risk of developing cancer and diabetes. In animal studies, the effects of stress persist for three generations. Until now there has been no mechanism identified by which the effects of lifetime events can affect subsequent generations.
Work by Isabelle Mansuy of the University of Zurich has now identified a mechanism in mice which appears to do just that. She has shown that fragments of miRNA are produced and passed on in sperm in response to stress or long-standing lifestyle factors such as overeating or lack of exercise.
Mansuy’s team looked at the sperm of adult mice that had gone through significant stress – being separated from their mothers at birth – and they found an increase in miRNA molecules. The behaviour of the stressed mice was altered – more daring behaviour than normal, less resilience in situations where endurance was needed. She found the same unusual molecules in the sperm of pups and grandpups of the stressed mice and broadly, the same behaviours.
Effectively, the study shows that the temporary experiences of one generation could influence the behaviour of future generations that were never exposed to the same experience.
So what does this mean for the slavery debate? There has been much said about the psychological and emotional stresses which have been placed on Black people who have been negatively impacted by slavery. Is this scientific confirmation that Black people could still be suffering from the after-effects of slavery?
The blogmaster invites you to join the discussion.