“By and large, the kids [conceived with in vitro fertilization] are fine. But if
there are [differences] you can measure, then you should.” — CARMEN SAPIENZA
Early disruption of schizophrenia
gene causes problems later
IVF kids show shift in
levels of gene activity
Researchers have found substantial
effects on the activity of dozens of
genes related to growth, metabolism
and related functions among children
conceived through in vitro fertiliza-
tion, epigenetics researcher Carmen
Sapienza of Temple University School
of Medicine in Philadelphia reported
February 21. “By and large, the kids
are fine,” Sapienza said. “But if there
are [differences] you can measure,
then you should.”
With IVF in general, “we’re kind of
doing an experiment here,” he said.
Epidemiological studies have revealed
a greater incidence of low birth weight
in children conceived with IVF. Among
other health issues, low birth weight is a
risk factor for obesity, hypertension and
type 2 diabetes later in life.
In the Oct. 15 Human Molecular
Genetics, Sapienza and his colleagues
described differences in DNA methylation on some 700 genes chosen
because of their known role in growth
and metabolism. The team found different methylation levels in 5 to 10
percent of those genes, investigated
in a group of children conceived via
IVF compared with children conceived
naturally.
Methylation does not affect the
genetic information itself, but how
genes are expressed throughout life.
Sapienza’s team determined that the
differences in DNA methylation patterns did translate to differences in
activity for some of the genes, several
of which are known to play a role in fat
cell development or insulin signaling.
Despite the differences, about
90 percent of the children in the IVF
group were still within the normal
range of gene activity levels, Sapienza
said. — Eva Emerson s
Brain tells signs from pantomime
The brain can apparently tell the difference between a word and a gesture—
even when the word is a gesture.
Karen Emmorey, a cognitive
neuroscientist at San Diego State
University, has been looking at the
brain activity of deaf people as they
interpret American Sign Language.
She showed 10 subjects pictures of
objects that have actions associated
with them — a cup for drink, say, or a
broom for sweep. She asked participants to either sign the ASL word that
goes with the picture or to pantomime
using the object. In some cases, such
as drink, the word and the gesture are
the same: Subjects pretended to hold
a cup in one hand and brought it to
their mouths. For other words, such
as sweep, the sign and the pantomime look different.
By taking positron emission tomography images of the volunteers’ brains
during the activities, Emmorey found
different regions of the brain lighting
up when the deaf subjects signed than
when they pantomimed, even when the
word and gesture were identical.
“For sign production we find language regions engaged,” Emmorey
reported February 19. But when subjects pantomimed, the brain regions
that lit up were those associated with
grasping, manipulation and motor
planning.
“The fact that many signs are
iconic doesn’t change the fundamental organization of language, nor does
it change the neural systems that
underlie language,” she said. — Lisa
Grossman s
