The world has seen many relationships end after the utterance of this sentence on the famous TV show, "Maury". As I was scrolling through Facebook the other day, I looked over at the "Now Trending" tab on the side and saw a link that said "
DNA: Father Failed Paternity Test Due to ‘Chimeric’ Genes, Researchers Say", so I of course clicked on it. What followed was very interesting. A couple from Washington used a fertility clinic to help them have a child. The pregnancy and birth went well, but they later found out that the child's blood-type did not match either parent, so they decided to do a paternity test, which the father failed. This lead them to assume that the clinic might have swapped the sperm samples with an unknown donor.
Simply put, a paternity test is done by taking saliva or blood samples from the child, mother, and father(s) in question and comparing the alleles to each other. The child's alleles should have several matches to the mother's and father's, some matches to a non-parent family member, and fewer to none matches to a stranger/non-family member (if the child has no matches, they are probably adopted).
The failed paternity test then led them to do a full DNA test on the father's and child's DNA, after which they found that there was a 10% match, suggesting that he was actually the child's uncle, rather than father. These tests were done using DNA from blood and saliva samples, so doctors then tested his sperm, which contained the match to the child. This phenomenon is called chimerism, which is when a person has extra genes/DNA that were absorbed from an unborn/miscarried twin in the womb. This theory of the man being a chimera supports the uncle results since the DNA in his gametes is ultimately from his unborn brother. Weird, huh?
What if the unborn twin had been a girl? Would that mean that this man's gametes would be eggs, and therefore make him unfertile, or would his sperm contain female DNA that would guarantee that the only children he and his wife could have were girls? The
news article I read only mentioned another case where the unborn twin was the same sex as the chimera, so it would be interesting to look into this possible scenario.
I wonder what the probability of cases like this happening are. Obviously, we don't have full data on even the frequency of fetal resorption if people like this are just finding out about their condition as fully grown adults; let alone would we have any ability to estimate their impact on false results of this type. It just makes me curious what the numbers might be, and what other factors like this might be out there. Maybe some of those cases where the mother was so certain and Maury slammed them down were not so clean cut! Someone call the show's lawyers! XD
ReplyDeleteThat's crazy! I think I've heard of a story similar to this, but this is still fascinating!
ReplyDeleteOne of my undergrad professors had a similar story! Apparently this man had committed a rape and murder so his sperm DNA was left at the scene. He got away with it for so many years because when he was tested, his DNA did not match that at the crime scene. However, a couple years later he was re-tested and this time it was a match. What had happened was the same thing, his blood and saliva had his DNA but his sperm had his twin brother's DNA. The man had eaten his twin in the womb, and therefore incorporated the twin's DNA into his. AMAZZINGG!!
ReplyDeleteThis is cool and interesting to know that it was due to an unborn twin. What my question would be, is that if there is maybe a better way to do paternity tests then if these cases have been witnessed. Is there a more sure fire way to guarantee that the paternity test worked even in this case.
ReplyDeleteThis was very interesting. I wonder how common this is.
ReplyDelete