Hold on to your chair. This is an unusual case of a man who failed a paternity test and was shocked to discover that his child's father is his own lost twin brother. Did the DNA test screw up? Geneticists said no.
Yes, for real. The father's DNA sample did not happen to match that of his child's. He even tried to carry out two paternity tests and without expecting, the results showed negative.
Perhaps such a case is rare, but is never impossible. Previous studies have even documented a few mothers who also failed maternity tests for their children. Such happens when the genome of the mother does not have the same sequence all throughout her body - that is, some parts may have a certain sequence while the rest may have another.
However, knowing it to happen in a male person is the first of its kind, and that there seems to be a mix-up between his own genome and his twin brother's.
It all started from a couple in the US who barely got their second child conceived. They asked for help and went to a fertility clinic where intrauterine insemination was performed. It is a procedure in which a man's sperm is concentrated and washed before inserting it directly to the uterus of the mother during ovulation. Such a method turned successful and resulted to a baby boy nine months after.
But what caught the attention of the parents was the fact that their child's blood type was AB, although theirs were both A. Such made them decide to undergo paternity test which the father eventually failed, and tried another one but still with no luck. The couple confronted the clinic, but was informed that there was possibly no mixed up of sperms as they were the only Caucasian couple on that day of the test, the other being African-American.
That's when Stanford University geneticist Barry Starr intervened. He suggested the couple to undergo a more powerful paternity test called the 23andMe genetic service which is known as good in looking at family relationships. The result in this particular test was more surprising than expected - the father of the child was actually his uncle, the man's twin brother.
There and then, a team of geneticists including Starr studied the case carefully, and they came up with the hypothesis that the man could possibly be a human 'chimera' - a person with a combination of different genomes. Their claims were supported by running another test and found that the man's DNA in his cheeks differed from that in his sperm. That can be explained by the idea that the father may have resulted from multiple fertilizations which originally led to twins but were eventually fused together to form one.
The man, therefore, is a mixture of himself and his twin brother. His 'major' genome in his sperm constitutes 90 percent and the 'minor' just 10 percent.
It is just unfortunate that the minor genome was the one passed on to his child.