The Nature of Nurture
by Sally Lehrman, from California

Darlene Francis is talking about the frontal cortex, decision making,
and high-stress profiles in rats when she suddenly shifts the focus to
poor, single, inner-city moms—that is to say, stressed-out humans.
Working with rodents, the behavioral neuroscientist points out, makes
it easier to study and talk about social problems without stirring up
a political battle. But if you want to understand the effects of
maternal stress on childhood development, Francis says, just look at
her rats.

As a graduate student, Francis conducted an experiment in which she
swapped pups between a litter of rats bred for calmness and another
that was predisposed to anxiety. The genetically calm mothers tended
to be better nurturers, licking and grooming their pups more than the
anxious mothers did. But when a calm, nurturing mother raised the
genetically anxious pup added to her brood, the adoptee switched
tendencies. The anxious rat behaved calmly throughout life, performed
better in cognitive tests, and was more willing to explore new
environments. The calm mother’s behavior, Francis discovered, had
caused permanent changes in the operations of the anxious rat’s genes.
Even more stunning: The acquired traits—calmness and nurturing habits—
were passed on to the anxious rat’s next generation.

In the question of nature versus nurture, we’ve embraced the view that
our fates are written in genetic code. The news in recent years has
been filled with reports about the isolation of genes said to “cause”
everything from diabetes to voter turnout. Increasingly, though,
researchers are finding that genes don’t tell the whole story.

In a rapidly developing field called epigenetics, scientists are
discovering that nutrition, exposure to toxics, even a mother’s touch
(or lack thereof) can cause heritable changes in gene expression
without any corresponding change in DNA sequence.

Francis’ work has been among the first to show that epigenetic
influences go far beyond the common conception of “environment” to
include things such as social interactions. With that in mind, her lab
at the University of California, Berkeley, collaborates with
scientists across the spectrum: in molecular biology, public health,
psychology, and even moral reasoning. The links may strike some hard-
core geneticists as alien territory, but with findings like Francis’,
doubters may soon find themselves arm in arm with the “soft” sciences.
Francis considers herself a member of both camps. “I’m a Ph.D. in
neuroscience, but at heart a social worker,” she says.

In the 1990s Francis took a break from her graduate studies at McGill
University to work with troubled young children in Montreal. She knew
all about their early life experience—many of her charges were the
children of friends she had grown up with. How, she couldn’t help but
wonder, had she ended up in a Ph.D. program while her friends were
visiting their kids in jail?

Such questions preoccupied Francis when she returned to school. She
already knew that social, economic, and emotional deprivation could
harm family relationships, and a resulting lack of nurturing could set
up a certain type of brain biology for children. The young rats’ genes
had been chemically repackaged in order to mobilize permanently
against stress and routinely pump out high levels of hormones such as
cortisol, in turn damaging learning capacity and heightening
fearfulness. And yet, Francis was sure that the reactive behavior
patterns apparently etched into the brain’s biochemistry could change.
In working with troubled children and their mothers, for example, she
had seen how transformative a simple thing like a weekend outing could
be. The question was, how?

Francis set up experiments to investigate what could damp down the
stress response in teenage rats. Enriched environments—cages with
plenty of toys and social companionship—changed both hormone levels
and behavior. Gene expression remained the same, however, suggesting
that the rats compensated in some other way. To better understand what
happens, Francis has begun a number of cross-disciplinary projects at
Berkeley on stress response, decision making, and external influences
on gene activity.

One of her closest collaborators is integrative biologist Daniela
Kaufer, whose work documents the role of RNA—long dismissed as DNA’s
poor sibling—in switching the functions for which DNA codes. Under
stress, Kaufer has found, molecules outside the genome change the RNA
in new ways, trimming and rearranging it to alter gene function.

Kaufer says that if researchers can break down the reprogramming in
the brain caused by early-life trauma or stress, possible
interventions may present themselves. Physical exercise, for instance,
is known to reset the molecular machinery. Yoga, meditation, and sleep
all can alter the stress response, muses the former yoga teacher.

For Francis, the study of how stress can work itself into our
biological inheritance remains deeply personal. “I’m a product of all
this stuff,” she says, referring to her hardscrabble beginnings back
in Montreal. Americans, Francis contends, think poor people are poor
because they make poor decisions. Francis believes the experience of
her rats points to something very different.



Sally Lehrman has reported for Scientific American and the Peabody
Award–winning, NPR-distributed series The DNA Files
(www.dnafiles.org). Reprinted from California(March-April 2008), the
alumni magazine of the University of California, Berkeley.
Subscriptions: $19.95/yr. (6 issues) from Alumni House, Berkeley, CA
94720; www.californiamag.org.

http://www.utne.com/2008-07-01/Science-Technology/The-Nature-of-Nurture.aspx?utm_medium=email&utm_source=iPost&utm_source=iPost&utm_medium=email

On Jun 25, 3:19 pm, Lance  wrote:
>
>
> For Francis, the study of how stress can work itself into our
> biological inheritance remains deeply personal. “I’m a product of all
> this stuff,” she says, referring to her hardscrabble beginnings back
> in Montreal. Americans, Francis contends, think poor people are poor
> because they make poor decisions. Francis believes the experience of
> her rats points to something very different.
>
Interesting, and I was with her argument through most of it. I'm not
sure about this paragraph, though. How do we go from rats, who have no
money at all, and, if given any, would use it for bedding, to
conclusions about poor people?

Peter Brooks wrote:
> On Jun 25, 3:19�pm, Lance  wrote:
> >
> >
> > For Francis, the study of how stress can work itself into our
> > biological inheritance remains deeply personal. �I�m a product of all
> > this stuff,� she says, referring to her hardscrabble beginnings back
> > in Montreal. Americans, Francis contends, think poor people are poor
> > because they make poor decisions. Francis believes the experience of
> > her rats points to something very different.
> >
> Interesting, and I was with her argument through most of it. I'm not
> sure about this paragraph, though. How do we go from rats, who have no
> money at all, and, if given any, would use it for bedding, to
> conclusions about poor people?

It is a bit of a leap.

Lance

On Jun 30, 9:32 am, Lance  wrote:
> Peter Brooks wrote:
> > On Jun 25, 3:19�pm, Lance  wrote:
>
> > > For Francis, the study of how stress can work itself into our
> > > biological inheritance remains deeply personal. �I�m a product of all
> > > this stuff,� she says, referring to her hardscrabble beginnings back
> > > in Montreal. Americans, Francis contends, think poor people are poor
> > > because they make poor decisions. Francis believes the experience of
> > > her rats points to something very different.
>
> > Interesting, and I was with her argument through most of it. I'm not
> > sure about this paragraph, though. How do we go from rats, who have no
> > money at all, and, if given any, would use it for bedding, to
> > conclusions about poor people?
>
> It is a bit of a leap.
>
Thanks for the confirmation, I sometimes worry that it is only me...