DNA Paternity Testing - theory explained 2

Guy fails paternity test because his unborn twin is the father At first they thought there must have been a mix-up, but this was even more bizarre. A 34-year-old man recently failed a paternity test because DNA from his unborn twin was passed onto his child rather than his own. This meant biologically the baby’s father was technically the man’s unborn brother. Yup, for real. The case has been written about in a study by geneticist Barry Starr at Stanford University. Let’s start from the beginning. The couple, who have not been named but are from Washington in the US, were having trouble conceiving their second child so they went to a fertility clinic. Intrauterine insemination was performed, where the man’s sperm was washed and concentrated before being inserted directly into his partner’s uterus during ovulation. The procedure was successful and nine months later a baby boy was born. That’s when things got a bit weird. The baby’s blood type was AB but both the mother and father were blood type A – a genetic head scratcher. ‘Both parents were A, but the child was AB,’ Barry Starr, a geneticist at Stanford University, told IFLScience. ‘There are rare cases where that can happen, but their first thought was that the clinic had mixed up sperm samples.’ The couple carried out two paternity tests and – to their disbelief – both came back negative. The man did not appear to be the baby’s father. However, the only other intrauterine insemination that had taken place at the clinic on the same day had been for an African-American couple and given the baby’s appearance a mix-up seemed unlikely. That’s when the couple’s lawyer contacted Stanford University geneticist Barry Starr in June last year, who suggested a more powerful paternity test called the 23andMe genetic service. This test was much more thorough and could determine whether there was a familial link. The results totally blew them away. The 23andMe test showed that the man was genetically the baby’s uncle. ‘That was kind of a eureka moment. Chimera reports are very rare, but they are real.’ Barry Starr said. DNA samples were taken from the man’s cheek to test their theory and that’s when they discovered that 10 per cent of the DNA carried in his sperm did not match the rest of his DNA. The man actually carried two sets of DNA – his own ‘major’ genome and his unborn brother’s ‘minor’ genome. The man also displayed two-tone skin, which he had been teased about in school, another indication that he carried two sets of DNA. They carried out another paternity test with the unborn twin’s DNA and found a match. This was the DNA that had been passed on to the child. ‘So the father is the fusion of two people, both the child’s father and uncle. That’s wicked cool,’ Barry Starr said. #DNA #geneticTest #dnaPaternityTest #GeneticPaternityTesting #genetics