Heterozygous 21 STR Loci and Triplet Alleles Observed in Population Genetic Analysis of the GlobalFiler STR loci in the Ghanaian population

Abstract

This study profiled 1,047 volunteers using the GlobalFiler™ Kit from the four main ethnic groups in Ghana: the Akan (282), Mole-Dagomba and Northern ethnic minority (253), Ewe (250) and Ga-Dangbe (262), representing about 98.4% ethnic coverage of the Ghanaian population.
The polymorphic nature of the African population was demonstrated during the profiling of the reference data set with the occurrence of some rare triplet variant alleles. At the TPOX locus, three tri-allelic were found with the allelic patterns 6-8-10, 8-9-10 and 9-10-11. In addition, tri-allelic patterns were seen at D5S818 (11-13-14) and D3S1358 (15-16-17).
Although the TPOX tri-allelic pattern has been reported in other populations including African, the D5S818; 11-13-14 has never been reported in an African population. It has however, been reported once with a frequency of 1 in 69,600 in a convicted offender case in the USA. The D3S1358; 15-16-17 pattern has not been reported in an African population.
In conclusion, the occurrence of rare alleles is illustrative of the genetic diversity within the Ghanaian population. This was further illustrated by the presence of three individuals that were heterozygous at all 21 STR loci.