DNA testing has become a standard legal identification method especially in criminal cases. DNA testing has also been applied in paternity disputes. However, it is a different thing for identical twins. Similarity in identical twins DNA profile have been debated so many years ago. Some criminal cases even came to a no conclusion case due to the lack of differences found in the DNA sequences amongst the identical twins.
Why do identical twins or monozygotic twins share the same DNA profile? This is mainly because the twins are growing from the same, single fertilized egg which then splits into tow and forms two individual embryos. Thus, the reason they have nearly identical genomes and cannot be differentiated using the traditional, standard DNA testing method.
Traditional DNA profile testing involves amplifying DNA fragments collected from a crime scene then compare with a suspect’s DNA profile. In normal case, this method of DNA testing is sufficient due to the fact that each individual’s DNA profile is vary, regardless of various types of samples recovered from a crime scene. This traditional method however is insufficient to pinpoint mutations in identical twins. Despite of sharing the similar DNA, the profiles are not necessarily exactly the same. This is due to the factors such as environmental factor that may contribute to the mutations of their DNA sequence. Hence, a more comprehensive methods and techniques might be needed to pinpoint this scarce mutations. In modern days, the identification and differentiation of an identical twins are possible with the introduction of next-generation sequencing. A group of scientists from Germany has claimed the effectiveness of this method by taking a close look at the base pairs of the complete human genome, comprising 3 billion-base-pair of DNA. What they examine was the mutations that randomly occurred during development. The mutations were found vary although only at a limited locations. These random mutations can be used to relate a crime to a twin. However, hopefully more research and analysis would be done so that this method can be improved in terms of its complexity