Paternity testing using 21 STR Loci in a biotechnology approach: case of Rwandan Population

INTRODUCTION: We focused on a sample size of 141 unrelated Rwandan persons to genotype21 STR loci that were relied up in establishing allele frequencies, heterozygosity and power ofexclusion. This study aims at exploring allele frequencies on a representative sample from Rwandanpopulation to determine probability of paternity for sampled families basing on polymorphic STRsloci, using 21 autosomal-STR loci by Genetic Analyzer 3500X.METHODS: This was an experimental study and global filer TM Express PCR Amplification kit wasused to amplify 21 autosomal STR loci.RESULTS: The total number of observed alleles was 270; the largest number of different alleleswas seen in SE33 and D18S51 loci. The locus with the highest heterozygosity was SE33, while locusTH01 had the lowest heterozygosity. The heterozygosity of the 21 STR loci ranged from 71.3%(TH01) to 91.6% (SE33) with an average of 81.1% a good indicator of high genetic variability. Forall microsatellites analyzed the power of exclusion ranged from 43.4% (TH01) to 78.1% (SE33)with an average of 58.2%. For seven of eight cases examined in paternity test alleged father wasnot excluded as biological father of child. The results found in examination of case 8 indicated thatthe alleged father was not the biological father of the child.CONCLUSION: Based on calculated statistical parameters, the population of Rwanda may usethese 21 STR loci as a vital tool for forensic identification and paternity testing.