From the Experts



Texas A&M University


Andrew Sarbah’s journey from Ghana to the country of his birth was uneventful until he landed there. The 15-year-old was moving back to London, UK to live with his mother Christine, siblings David, Joyce, and Diana after spending 11 years with his father in Ghana. As he reached the immigration counter and handed over his British and Ghanaian passports for verification he was met with an eye of suspicion. His broken English did nothing to alleviate these doubts. Andrew’s British passport had a picture of him as a baby. The authorities suspected that the passport was forged and that he was not the person he claimed to be. Andrew claimed that he was born in London to parents of Ghanaian descent and had moved to Ghana at the age of four to live with his father after his parents had separated. The authorities had reasons to believe that Andrew was substituted for another unrelated boy or a close cousin to illegally immigrate into the country. So they denied him entry to the UK as a British citizen but granted a temporary admission till his immigration status was determined.

Unhappy with the situation Andrew’s family took legal recourse and started gathering evidence to corroborate his claims. The family also decided to undergo conventional blood typing, tissue typing, and serological tests to establish a biological relationship. The result of these tests identified a relationship between Andrew and Christine but the nature of this relationship was not conclusive. The test results proved with 98% certainty that Andrew was Christine’s son and the only other possibility to get such a test result was if Andrew was a son of the same father and one of Christine’s sisters. So, the testimonial evidence and test results were not considered undisputable by the Home Office to change his immigration status.

While the Sarbah family was searching for incontrovertible proof of Andrew’s kinship, their immigration attorney Sheona York came to know about a new genetic method that could identify individuals and parentages based on their DNA. The test was known as DNA fingerprinting and York wanted to use it for the Sarbah case.

Just like fingerprints that are unique for every individual, DNA fingerprints were claimed to distinguish individuals based on unique patterns in their DNA. The method was developed by Professor Alec Jeffreys at the University of Leicester who claimed that the probability of two individuals having the same DNA fingerprint was less than 1 in 33 billion. Though 99.9% of the genome of an individual is identical to any other individual, the 0.1 % variation makes them unique. These differences known as DNA polymorphisms can be exploited to distinguish individuals from one another. These polymorphisms are inherited by a child from parents and hence can be traced back to them. In Jeffreys’ method of DNA fingerprinting DNA is extracted from the sample, digested (cut) with a specific restriction enzyme, separated by agarose gel electrophoresis, transferred to nitrocellulose membrane (southern blotting), and hybridized to a radioactively labeled probe. Further, an X-ray film is developed which shows a pattern of bands (DNA fingerprint) in areas where the DNA binds to the probe. A comparison between bands from different individuals can reveal the relation between them.

Although this technique was still in development at that point and required further fine-tuning Jeffreys was willing to use it for Andrew Sarbah’s case. In an ideal situation analysis of DNA samples of Christine, Andrew, the father, and Christine’s sister would easily prove the familial relationships. But in this case, the DNA samples of the father and any of Christine’s sister were not available. Furthermore, Christine was not sure about the paternity of Andrew which complicated the situation. However, the parentage of Andrew’s siblings was undisputed and their DNA could be of help. So the DNA fingerprints of Andrew, his mother (disputed), one brother, and two sisters were developed. The first step was to recreate the DNA fingerprint of the father from the three undisputed siblings. For this, DNA fragments absent in the mother but present in at least one of the three undisputed siblings were identified. On comparing the father’s reconstructed DNA fingerprint with that of Andrew’s, nearly half of the DNA fragments matched. This strongly indicated that Andrew had the same father as his siblings. The remaining DNA fragments in Andrew’s DNA fingerprint matched with Christine, confirming her as the biological mother. Based on the results of DNA fingerprinting the probability that Andrew was not related to the family, had an unrelated woman or any of Christine’s sister as his mother was very low.

Armed with this irrefutable evidence of a relationship, attorney York presented the data to the immigration court. On the other hand, the Home Office did not have any substantial counterevidence. While the chair of the proceeding considered the evidence, he did not want to set a legal precedent for deciding an immigration appeal based on a new, untried, and untested scientific technique.

This meant that the case would go to the High Court unless the Home Office was willing to withdraw it. Finally, the case against Andrew Sarbah was dropped by the Home Office and he was granted citizenship to reside in the UK, reuniting him with his family.

Though the validity of the DNA fingerprinting was never questioned in the court, the victory in the Sarbah case gave it credibility in the eyes of the public. This was a case where science came to the rescue of a young boy who otherwise would have been deported for no fault of his own. Eventually, in 1986 the magistrate accepted DNA evidence to be reliable and in 1989 DNA fingerprinting was recognized as a legal method of determining paternity in immigration cases.

Note: The story of Alec Jeffreys discovery of DNA fingerprinting and its use in solving cases has been dramatized into a television series Code of a Killer and is available for viewers on YouTube and other OTT platforms.

References (Oct-20-A1)

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