Allelic frequency variation of ACKR1 in three Algerian populations: Zenata, Reguibat, and Oran

INTRODUCTION

The discovery of the Duffy antigen is of great significance, given its essential role in immune response and various physiological processes. Genetic mutations in the Duffy gene not only affect antigen expression but also result in different antigen types. This underscores the importance of genetic characterization for clinical studies and exploring genetic diversity within the population. This study primarily aims to genetically characterize the Duffy blood group within three Algerian populations: the Zenata, Reguibat, and Oran populations.

METHODS

The genetic polymorphism of the Duffy erythrocyte group was examined, focusing on five allelic versions of the ACKR1 locus: FY*01, FY*02, FY*X, and silent alleles FY*01 N.01 and FY*02 N.01. A total of 223 Algerian individuals, including 90 from the Oran population, 66 from the Zenata population, and 67 from the Reguibat population, were analyzed using the polymerase chain reaction with sequence-specific primer (PCR-SSP) method. The results revealed the presence of the silent alleles (FY*01 N.01 and FY*02 N.01) in all three populations, with a total frequency of 78.03% in the Zenata population. Additionally, the FY*X allele was exclusively detected in the Reguibat population, with a frequency of 0.75% CONCLUSION: This study provides valuable insights into the allele and genotypic frequencies of the Duffy system in the Zenata, Reguibat and Oranpopulations, contributing to our understanding of the genetic history and origins of the Algerian population. Further research incorporating additional genetic markers and establishing a comprehensive database would enhance our knowledge in this area.

Frequencies of D19S433 silent alleles in a Japanese population of 1501 individuals and their effect on likelihood ratios calculated in kinship tests

Although silent alleles in D19S433 typing using the GlobalFiler PCR Amplification Kit have been reported, the exact frequency of the D19S433 silent alleles in population data of 1501 Japanese individuals, which are widely used for the assessment of Japanese STR typing results, is unclear. In this study, we examined the exact D19S433 silent allele frequency in this population data. We newly observed the G32A variant causing silent alleles at D19S433 in five samples. Combining them with data including 30 samples with the variant reported previously, we determined that the total frequency of the silent alleles (i.e. the frequency of the G32A variant) in the 1501 Japanese samples was 0.0117 (35/3002). Using the D19S433 allele frequency data, we evaluated the effect of presence/absence information for the D19S433 silent allele on kinship tests. Likelihood ratios (LRs) were calculated for both simulated parent-child and full sibling cases, revealing that the LR may change by approximately 10^-2 to 10³ fold when the presence/absence of the D19S433 silent allele is revealed in a kinship test. Therefore, if a sufficiently large or small LR is obtained, there is little need to determine the presence/absence of the D19S433 silent allele in Japanese kinship tests using GlobalFiler. This study will be beneficial for the assessment of Japanese human identification and kinship test results using GlobalFiler.

A silent allele in the locus D5S818 contained within the PowerPlex®21 PCR Amplification Kit

Three paternity tests cases were found with a single locus mismatch at the locus D5S818 with PowerPlex®21 PCR Amplification Kit (Promega). Forward and reverse primers were redesigned to type the samples again and to evaluate if there were alleles dropped out. The results showed the existence of a silent allele 12 in all the three families, due to a point mutation that changed cytosine to adenine at 90 nucleotides upstream from the 5' end of the AGAT repeat sequences in all the six individuals. A single locus mismatch due to a silent allele may occur in any locus using any kit. Therefore, we recommend using multiple kits to confirm the results in paternity testing cases with mismatches, especially when there is a single locus mismatch with homozygote involved.