In this study, 268 samples for unrelated males belonging to the five major human subpopulation groups in Ghana (Akan, Ewe, Mole-Dagbon, Ga-Dangme and Guang) were genetically characterised for 23 Y chromosome short tandem repeat (STR) loci using the Powerplex® Y23 STR kit. A total of 263 complete haplotypes were recorded of which 258 were unique. The haplotype diversity, discriminating capacity and match probability for the pooled population data were 0.9998, 0.9627 and 0.0039, respectively. The pairwise genetic distance (RST) for the Ghanaian datasets and other reference populations deposited in the Y-STR Haplotype Reference Database (YHRD) were estimated and mapped using multidimensional scaling (MDS) plot. The Guang and Ewe were significantly different from the Akan, Mole-Dagbon and Ga-Dangme. However, the five Ghanaian datasets were all plotted close together with other African populations in the MDS data mapping.
Short tandem repeat (STR) loci are widely used as genetic marker for ancestral and forensic analyses. The latter application includes for paternity testing and DNA profiling of samples collected from scenes of crime and suspects. This survey provides the first dataset for 21 STR loci across the Akan population in Ghana by genotyping of 109 unrelated healthy individuals using Investigator 24plex kit. None of the STR loci screened deviated from Hardy-Weinberg equilibrium after applying Bonferroni correction. Overall, 224 unique alleles were observed with allele frequencies ranging from 0.005 to 0.518. The combined match probability, combined power of exclusion and combined power discrimination were 1 in 4.07 × 10-25, 0.999999999 and 1, respectively. Principal coordinate analysis carried out using 21 STR allele frequency data mapped the Akans with Nigerian subpopulation groups (Hausa, Igbo and Yoruba), but separated from Thais of Thailand, Chechen of Jordan and Tijuana of Mexico.
Autosomal short tandem repeat (STR) population data collected from a well characterized population are needed to correctly assigning the weight of DNA profiles in the courtroom and widely used for ancestral analyses. In this study, allele frequencies for the 15 autosomal short tandem repeat (STR) loci included in the AmpFlSTR® Identifiler® plus kit (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, VWA, TPOX, D18S51, D5S818, FGA) were obtained by genotyping 332 unrelated individuals of Ghanaian origin. Statistical tests on STR genotype data showed no significant departure from Hardy-Weinberg equilibrium (HWE). The overall match probability, combined power of exclusion and combined power of discrimination for these loci were 1 in 3.85 × 1017, 0.99999893 and 0.99999998, respectively. Polymorphic information content (PIC) greater than 0.70 was observed for all loci except TH01 and D13S317. These statistical parameters confirm that this combination of loci is valuable for forensic identification and parentage analysis. Our results were also compared with those for 20 other human populations analyzed for the same set of markers. We observed that the Ghanaian population grouped with other African populations in two-dimensional principal coordinate (PCO) and a neighbor-joining (N-J) data mapping and placed closest to Nigerians. This observation reflects cultural similarities and geographical factors, coupled with the long history of migration and trading activities between Ghana and Nigeria. Our report provides what we believe to be the first published autosomal STR data for the general Ghanaian population using 15 loci genotyped using the AmpFlSTR® Identifiler® plus kit methodology. Our data show that the loci tested have sufficient power to be used reliably for DNA profiling in forensic casework and help to elucidate the genetic history of people living in the country.