Research puzzles Man is at the same time father and uncle

A couple from the United States has experienced an incredible story: after the birth of their child, a blood test proves that the man can not be the father of the child. At least not only - because further research shows that he is also the uncle of the boy. A medical phenomenon for which there is still no scientific explanation.

Blood group test excludes possible paternity of the man
The nightmare for all newly-baked parents: A couple gets a child through artificial insemination, but after birth, it turns out that this has a blood type that can not actually be. Because the test had resulted in the baby "AB", although both parents have blood type A. Consequently, the man could not be the biological father of the boy, because both parents are "homozygous" A or B, they can not have children with a mixed blood type.

Scientifically inexplicable: According to DNA father is at the same time uncle. Picture: goodluz - fotolia

Father and son share only 25 percent of the DNA
Since the result was also confirmed by a second test, the parents grew worried that it had come in the context of artificial insemination perhaps in the clinic to a confusion of sperm donation. They sought help from a lawyer and also contacted Barry Starr, a geneticist at Stanford University, who also runs the Ask a Geneticist blog. He recommended a re-examination with a genetic test from the supplier 23andMe, which he then evaluated and came to an astonishing conclusion: "The man is two things - father and uncle," said Barry Starr. According to the genetic test, father and son would only share 25 percent of the DNA, just as other close relatives such as uncle, niece or nephew are. In a "real" paternity, however, the child inherits 50% of his DNA from his father.

Foreign DNA can remain in the body for years
In the next step, the sperm of the father was examined. It turned out that while 90 percent of his own DNA was to be found in this, the other ten percent was that of his twin brother, who was never born. What sounds unbelievable, however, is not out of line with the current state of research. Because it has been known for some years that cells are exchanged between the embryo and the mother during pregnancy via the placenta, which remain in the body after birth.

However, it is still unclear how this phenomenon can be scientifically explained. So far, the so-called "cake" as a "barrier", which ensures that the maternal blood does not mix with the blood of the child. But even after miscarriages or blood transfusions, the body absorbs foreign cells that can persist for years. "There are many more twins than is commonly believed," said Peter Pharoah of Liverpool University, a few years ago, according to The World. "During conception, the chance is one in 20, but only one out of 40 births will actually give birth to a healthy duo, the rest will not survive the nine months in the uterus," the newspaper quotes the researcher.

First case of this kind
"To our knowledge, this is the first reported case where paternity was initially excluded by standard DNA testing and later re-included as the result of analysis of various tissues," Barry Starr reports in a small study accompanying the study Case was published.

"This case of chimerism, resulting from the false exclusion of paternity, is considered unusual; but with the inclusion of assisted reproduction, this result could occur with increasing frequency, "the expert continues. (No)