"Male" DNA found in "female" brains

A groundbreaking study raises questions about gender distinctions

Published September 27, 2012 7:50PM (EDT)

      ((Wikimedia/Richard Wheeler - Zephyris))
((Wikimedia/Richard Wheeler - Zephyris))

Researchers have found male DNA inside female brains for the first time, prompting paradigm-shaking biological questions.

According to a study published in PLOS ONE journal and picked up by Canada.com, male microcherism -- "the 'intermingling' of small numbers of cells or portions of DNA in a person from a genetically different individual" -- was discovered in the brain of 63 percent of female patients tested.

It is thought that the male DNA found in the female brains likely derived from previous pregnancies with XY [male] chromosomed babies. (Indeed, it's worth pointing out that the designation of "male" and  "female" DNA, as determined by it containing XY or XX chromosomes, is contentious in gender theory, since the way the terms "male" and "female" function in the world is not entirely determined by chromosomes.)

The new findings are significant for two reasons. First, researchers found that women with Alzheimer's disease appeared to have lower concentrations of "male" DNA in brain regions most affected by the disease. This could be a crucial finding for scientists researching the condition.

Second, as the study's senior author, Dr. J. Lee Nelson of the University of Alberta, pointed out, the findings "point to the need for a new paradigm of what self is, biologically." If one individual can have "immigrant" DNA intermingled in his or her cells, the notion of DNA as a unique person identifier is destabilized.

Nelson notes, “I think we’re better off thinking of it [the biological self] as an ecosystem, rather than as a singular genetic template, with more genetic and cellular diversity than we previously thought.”

Similarly, the designation of certain DNA as male or female is highlighted as problematic in findings like these.

By Natasha Lennard

Natasha Lennard is an assistant news editor at Salon, covering non-electoral politics, general news and rabble-rousing. Follow her on Twitter @natashalennard, email nlennard@salon.com.

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Alzheimer's Disease Dna Gender Research Science