Sibling Cells Transferred to Puppies in the Womb: New Implications for Microchimerism

Not all of your cells may actually be yours. Some specific individuals actually possess a small number of cells in their bodies that are not genetically their own, a condition known as microchimerism. Now, scientists may have found a bit more about this phenomenon with the help of puppies.

Previously, researchers have noted that microchimerism can also exist in dogs. This condition most often occurs when a mother gives birth to a child. Cells from that child can be left within a mother's body and continue to live, despite being a different genetic makeup than surrounding cells. Now, though, researchers have discovered evidence that these cells can then be passed on to other children that the mother may give birth to at a later time.

"We already have some evidence that microchimerism may increase risk of thyroid disease while lowering the risk of breast cancer in women," said Jeffrey Bryan, one of the researchers, in a news release. "The pet dog represents an excellent model of many ailments in people, and the presence of fetal microchimerism in dogs will allow studies which further clarify its role in health and disease. Knowing that the condition can be passed on through birth will help us track the condition and its effects through several generations of animals."

In this particular study, the researchers found microchimerism in a female dog that had given birth to both male and female puppies. More specifically, they discovered cells with Y-chromosomes in the mother after these births. This meant that the mother had male cells present in her female body, left over from the pregnancy. That's not all the researchers found, though; they also discovered genetically similar male cells in the mother's female puppies from a later litter. This seemed to indicate that this condition could be passed down between siblings.

"These new findings are significant because they suggest that the movement, or trafficking, of fetal cells is quite extensive in dogs, as has been suggested in people," said Bryan in a news release.

In fact, this trafficking can have an impact on health, disease and therapy. The findings therefore represent a new way for researchers to better understand and study this condition. This, in turn, could allow scientists to better understand how these cells impact people in the future.

The findings are published in the journal Chimerism