The impact of motherless paternity testing in a South African population

Abstract

Background: Paternity investigations play an important role in determining biological relatedness, and in South Africa, the outcome of these investigations impacts medical, judicial and home affairs decisions. Short Tandem Repeat (STR) analysis is utilised to perform paternity and kinship analysis, due to the polymorphic nature of STR loci. The cost associated with paternity testing is high, and there is a demand for motherless testing.
 Objectives: This study aims to determine what the impact of motherless testing would have been by evaluating 6182 pa- ternity trio cases.
 Methods: The AmpFLSTR™ Identifiler™ PCR Amplification kit was used to profile each of the trio cases. A scenario was created where the mother was eliminated from the test results to determine if the paternity outcome would change.
 Results: Putative fathers were excluded in 27% of all cases, and in 2.5% of those cases, putative fathers would have been falsely included, had the mother not been tested. These false inclusions are attributed to coincidental STR loci that are shared between the mother and the putative father. The addition of loci to the STR profiling kit may resolve the issue; however, comparable STR data with more loci will have to be evaluated to ensure it overcomes the issue of coincidentally shared loci between unrelated individuals.
 Conclusion: We would recommend that within our setup and within similar setups, the mother always be included for test- ing, except in extreme scenarios such as death. False inclusion of putative fathers could have serious legal implications for testing laboratories.
 Keywords: Motherless paternity testing; South African population.

Analysis of data and common mutations encountered during routine parentage testing in Zimbabwe

“…We observed an overall parentage exclusion rate of 31.16%. The paternity exclusion rate was 32.33 which is comparable to our previous findings 10 but slightly higher than other reported rates 9 , 11 – 13 . This could be because exclusion rates were estimated from cases that arose from doubts regarding biological parenthood.…”

“…Some of the reasons why it remains a popular test include affordability, privacy where the father does not want the mother to know of the tests and the fact that many of the cases were regular (non-legal) tests where the participation of the mother was optional. Some countries however discourage the motherless paternity tests to reduce the risk of false inclusions especially in cases where fewer STR markers are used, and the case background is not known 7 – 9 . As expected, maternity tests were not popular for solving parentage disputes.…”

Utilizing Massively Parallel Sequencing (MPS) of Human Leukocyte Antigen (HLA) Gene Polymorphism to Assess Relatedness in Deficiency Parentage Testing

“…In addition, when all the above triplet cases were further analyzed without investigation of the mother's genetic profile from the probability calculation, this displayed a remarkable decrease in the simulated duo cases below 0.999 compared with that of the trio cases, and the difference became even more significant when the aSTR POAs were presented with high frequency in the population study [17]. Also, while in the two triplet cases, one discrepancy was shown between the AF and the child in question, this discrepancy was eliminated when the DNA profile of the mother was missing from the analysis, which was an event observed in other studies [38]. Our results led to the conclusion that when simulating the duo from trio families, the mother's genetic profile can hide additional mismatches, providing enough certainty to include the putative father [39].…”

Disputed paternity presumption in Burkina Faso: determination of the biological fathers of children using ABO-rhesus/hemoglobin electrophoresis and STR assays

“…STR markers provide sufficient discriminatory power to exclude or include an alleged father in contested paternity cases. Unlike ABO-rhesus/Hb electrophoresis techniques which are based on the agglutination of red blood cells and hemoglobin, the STR technique determines the genetic profile of the DNA which contains the genetic information that is unique to each individual [ 29 ]. Because of the limitations of ABO-Rhesus/Hb electrophoresis, the PCR technique became the standard process for DNA paternity testing because PCR technology allows amplifying a very small quantity of DNA to increase the amount of DNA up to billions of copies of the same DNA for testing and analysis [ 28 , 30 ].…”