If you're a woman who
has been pregnant with a male fetus, you may have male DNA permanently in your
body, according to a study that found such genetic material in the brains of
women.
The study, published
in PLoS ONE, is the first description of male microchimerism in the female
human brain. Microchimerism is when someone harbors cells that came from a
genetically distinct individual. Or, in the immortal words of the Monkees
(singing a Neil Diamond penned song), a person can be A Little Bit Me, A Little
Bit You.
The serious side of
this is that scientists working at the Fred Hutchinson Cancer Research
Center have linked the phenomenon to
autoimmune diseases and cancer, sometimes for better and other times for worse.
Lead author William
Chan, who is in the Department of Biochemistry at the University of Alberta,
conducted the research while working in the lab of J. Lee Nelson, a member of
the Center’s Clinical Research Division and a leading international authority
on microchimerism.
The scientists
believe it is likely that fetal cells frequently cross the human blood-brain
barrier and that microchimerism in the brain is relatively common. Until this
study, it was not known whether these cells could cross the barrier in humans.
According to a press
release issued by the cancer center:
The researchers
examined brain autopsy specimens from 59 women who had died between the ages of
32 and 101. Male microchimerism was detected in 63 percent of subjects, was
distributed in multiple brain regions and was potentially persistent throughout
the human lifespan; the oldest female in whom male fetal DNA was detected in
the brain was 94.
Twenty six of the
women had no neurological disease and 33 had Alzheimer’s disease. The brains of
women with Alzheimer’s had a somewhat lower prevalence of male microchimerism,
which appeared in lower concentrations in regions of the brain most affected by
the disease. However, the authors noted that the small number of subjects and
largely unknown pregnancy history of the women means a link between Alzheimer’s
disease and level of male cells of fetal origin cannot be established.
"Currently, the
biological significance of harboring male DNA and male cells in the human brain
requires further investigation," Chan was quoted as saying in the release.
Prior research does,
however, suggest that women who harbor male DNA might be protected against some
types of cancer, such as breast cancer, and autoimmune disease, like rheumatoid
arthritis. It may, though, increase the risk of other cancers, such as colon
cancer.
Many studies suggest
that just having a child affects the future health of the mother, and not just
because the kid could drive her crazy or, conversely, help to improve her lot
in life. At least mothers now know that their sons might not ever fully leave
them, even after they move out of the nest.
(Image: Taylor
Schlades)
