Population Structure and Genetic Relationships among Nigerian Ethnic Groups (Ibibio, Igbo, Hausa, Tiv and Yoruba) Based on Nine Short Tandem Repeat Loci

Abstract

The genetic relationships between populations can be detected with the use of genetic markers. This study investigated the genetic relationships between five Nigerian populations of Igbo, Ibibio, Yoruba, Tiv and Hausa origin using nine short tandem repeat markers. The nine loci and the sex-typing marker amelogenin were combined into multiplex assays and tested by PCR followed by polyacrylamide gel electrophoresis on 50 individuals per population. The study revealed that four (4) of the nine (9) loci had F_ST values between 0.001 and 0.500 in the five populations, indicating that population substructure had almost disappeared in the pooled population. The molecular variance (AMOVA) for the pooled population revealed a variance of 3.850 for individuals and a variance of 0.0004 for among populations. Principal component analysis (PCA) revealed four heterogeneous clusters. The total variation explained by the first three axes of the PCA was 32.86%. All the populations had a pairwise population matrix of Nei genetic identity greater than 0.895 based on these loci. Both the pairwise population matrix and a dendrogram constructed based on the allele frequencies of these loci indicated that the Igbo and Yoruba ethnic groups had the highest genetic similarity (0.993) among the evaluated populations. The pairwise population matrix of Nei genetic distance showed that Igbo and Tiv and Igbo and Ibibio had genetic distances of 0.14 and 0.15, respectively, which were the greatest for all pairs of the five populations.