KEEP IN MIND
You might not have to look too far back
in your family history to find a traumatic
event that left its mark on one of your
ancestors. Perhaps someone was touched
by war, or grew up in a residential
school, or lost their home in a natural
disaster, such as a fire or flood.
We may think the difficult events our
forebears experienced are safely locked in
the past—they can’t hurt us now.
But can they?
Researchers are finding the stress
experienced by a parent, grandparent
or even a great-grandparent can reach
through the years and adversely affect
their children, grandchildren and great
pass from one
Understanding the ‘ghosts in the genes’
“A term that’s sometimes used
when we talk about ancestral stress is,
‘ghosts in the genes,’ ” says Dr. Keiko
McCreary, a recent PhD graduate at the
University of Lethbridge whose thesis
examined multi-generational stress in
Research shows that while stress
doesn’t change the genes themselves,
it can change how the genes switch on
and off in future generations. Animals
with an ancestor who was under stress
can have their own responses to stress
shaped by experiences they were never
The potential effects are worrisome.
McCreary says animals whose ancestors
were stressed have higher levels of stress
hormones, age faster, are more likely to
experience heart or kidney failure, and
are prone to other health problems.
In humans, the stress of previous
generations can have similar effects and
may also cause depression and anxiety.
Ancestral stress can turn a normally
cautious person into a risk-taker, or make
a risk-taker become more cautious and
withdrawn. Sometimes such behavioural
changes can have benefits, but it’s not
always easy to tell.
“The scary part is that you can’t predict
what level of stress will be toxic or
transferable to subsequent generations,”
McCreary says. “Stress is one of those
WRITTEN BY GREG HARRIS
ILLUSTRATED BY MICHAEL BYERS