Womb for improvement
Einstein wannabes should choose their mothers with care
New Scientist, 07 March 1998
wombs can produce smarter kids, scientists in the US suggest. Their
work shows that genetically identical mouse embryos implanted in
different wombs end up performing differently at mental tasks. This is
the first time that the uterus itself has been clearly implicated in an
offspring's long-term cognitive abilities, they say.
Denenberg and his colleagues at the University of Connecticut in Storrs
and the Jackson Laboratory in Bar Harbor, Maine, raised a strain of
mice that suffers from an autoimmune disease rather like lupus in
humans. The brains of around half these mice have slight structural
deformities which bear a striking resemblance to structural
abnormalities found in the brains of human dyslexics, says Denenberg.
researchers wanted to test their hypothesis that time spent in the
wombs of mothers with autoimmune disease could have a negative effect
on performance. Using a genetically identical group of mouse embryos
from the autoimmune strain, they transplanted one-third into the uteri
of mothers from a strain that was unaffected by the disease.
third, controlling for the effects of surrogacy, were transplanted into
the wombs of other autoimmune mothers. The others were allowed to
gestate normally. All were raised from birth by mothers from the strain
not affected by autoimmune disease.
Once they had been weaned,
the mice were put through a battery of five learning tests. In one test
at 10 weeks, for instance, they had to learn which way to turn in a
maze filled with cul-de-sacs. In another at 11 weeks they had to find a
submerged platform while swimming in a tub of water. Later, at 12
weeks, they had to work out how to avoid getting a light electric shock.
the mice showed competence in learning, but in four of the five tests,
the mice that developed in the womb of a mouse with no autoimmune
disease did better—even if they had inherited the brain abnormalities
associated with the autoimmune disease. "Presumably the anomaly acts to
impair the behaviour of the mouse," says Denenberg. But gestation in
the hybrid uterus seems to mitigate the problem, he says. "We're
delighted that we've found some positive contributions."
thinks that the difference could be due to some subtle biochemical
factors in the uterus. He believes that every mother may affect her
offspring in slightly different ways. "The uterine environment can have
long-term broad and beneficial behavioural effects," the team says in
last week's issue of the journal Neuroreport(vol 9, p 619).
expects the study to raise interesting questions about surrogate
motherhood in humans and even the prospect of artificial wombs. But
more importantly, it may highlight the contribution that good general
maternal health can have on cognitive abilities. "Maybe we ought to
think more seriously about the physiology of gestation," he says. "Are
there ways to prepare a non-pregnant uterus for pregnancy? An
`operation head-start' for the uterus?"