Male DNA found in female brains may provide health benefits

Researchers at the Fred Hutchinson Cancer Research Center in Seattle have found that female brains often contain male DNA. The study found that male DNA is transferred to females during pregnancy and can travel to the brain. This process, called microchimerism, happens when mothers and their fetuses exchange cells and other genetic material. The study examines women with and without Alzheimer's disease to try to determine whether the male DNA provides health benefits to the females.

If a woman is pregnant with a boy, she may end up with male DNA in her body that can remain there for the rest of her life. This also happens with female babies, too, but it is difficult to distinguish between microchimerisms of two females, reports Fox News.

During pregnancy, genetic material is exchanged both ways between mother and fetus. Other studies have been done to observe fetal DNA in the mother, but this is the first of its kind to confirm that fetal DNA can cross the blood-brain barrier and stay there after pregnancy. These findings are of interest to researchers because they want to determine what role the cells have in health and disease.

Autopsies were performed on 59 brains of deceased females, 26 were free of neurologic disease while 33 had Alzheimer's disease. Microchimerism was detected in 63 percent of those brains. Male DNA was found across multiple regions of the brain; they were not localized to one region. The microchimerisms may linger for a lifetime. The oldest female in the study with male DNA found in the brain was 94 years old. The women who were diagnosed with Alzheimer's disease had lower concentrations of male DNA in their brains than those who were free of the disease.

Other studies have found that male microchimerism in females can be both beneficial and harmful. In a breast cancer study, the male DNA played a protective role, and females with male DNA present in their systems had a lower rate of breast cancer than those who didn't. A colon cancer study had the opposite results; higher rates of the disease were found in women with male microchimerism.

Scientists believe that the protective benefits are a result of the male DNA boosting the immune system of the female by providing alternate ways to recognize antigens or malignant cells. One of the next steps in the study is to find out if the male cells can differentiate into other cells to perform other functions in the body of the female.

Photo courtesy of moyerphotos via Flickr.