Your recent article “Why capillary electrophoresis is reliable for paternity Tests—Expert” (March 4, 2025) presents an important discussion on DNA analysis methods. However, it does not fully reflect recent advancements in the field. While capillary electrophoresis has been a long-standing technique and the most reliable method for paternity testing historically, next-generation sequencing now offers superior accuracy and reliability.
CE technology has been in use for many human identification applications, such as paternity testing, forensic criminal investigations and disaster victim identification, since the early 1990s. While it was once considered the gold standard for HID testing around the world, scientific advancements have led to more precise alternatives. Laboratories around the world are now adopting an NGS for HID testing. This well-established technology has been routinely used for medical diagnostics for over two decades, as well as in many other types of molecular biological research.
Dr Emeka Obiodunukwe is correct that CE short tandem repeat analysis typically analyses between 13 and 27 markers to confirm a person’s identity. However, it is not possible to use more markers due to an inherent limitation of how many markers CE can analyse simultaneously.
NGS overcomes this challenge: The most widely used NGS kit for paternity testing utilises 52 STR markers. More markers mean more accuracy and, therefore, more reliable results. Advantages of NGS for paternity testing include:
Enhanced accuracy: NGS reads the DNA sequence instead of simply measuring the size of DNA fragments, as CE does. This allows for greater accuracy and comparison of additional variants in addition to the STR length. This is crucial when comparing closely related individuals. Think of it as the equivalent of seeing the DNA profiles in full HD instead of on a black and white TV.
Reduction in artefacts: NGS eliminates common artefacts that historically complicate CE-based DNA profiling, such as spectral pull-up, preferential amplification, or dye blobs. This leads to reduced reporting errors and also reduces the need for repeated testing.
Increased sensitivity: NGS delivers more reliable data and information correct in the first analysis attempt. It also enables newer techniques such as non-invasive prenatal paternity testing, which can determine paternity as early as 6 weeks into pregnancy by simply using a blood sample from the mother, posing no risk to the fetus.
Comprehensive kinship analysis: The increased number of genetic markers used in NGS allows for more complex kinship testing without the need for additional STR testing, reducing both cost and processing time.
Concerns about NGS software analysis requiring more advanced expertise and complex data analysis are often overstated when it comes to paternity testing. In fact, modern NGS software is designed as a semi-expert system, reducing the workload for the DNA analyst compared to traditional CE methods.
Many countries around the world have already adopted NGS into their routine paternity testing procedures, as it has many advantages over CE analysis. Embracing newer technologies like NGS is crucial to ensuring that paternity testing in Nigeria meets the same standards as in other countries.
- Richard Kessell is the HID & Forensics Applications Manager, Europe, the Middle East and Africa
