Genetic diversity and population structure of Chrysichthys nigrodigitatus from Niger Delta based on AFLP analysis

Abstract The silver catfish, Chrysichthys nigrodigitatus is an important food fish in the Niger Delta. To understand the genetic variations and population structure in Nigeria’s Niger Delta, eighty-eight individuals collected from 7 locations were analyzed based on amplified fragment length polymorphism (AFLP) analysis. A total of 243 bands were identified using 4 AFLP primer combinations. The average gene diversity was 0.1708 ± 0.1547 and Shannon’s information index was 0.2792 ± 0.2224. The pairwise F st values ranged from 0.133 to 0.796. The results of AMOVA analysis indicated that 19.03% of the genetic variation was contained among three groups. The gene flow estimates (Nm) demonstrated that different degrees of gene flow existed among populations ranging from 0.064 to 1.630. Two clades were recognized on the UPGMA tree. The results supported that freshwater or brackishwater habitat, limited long-distance dispersal of the adult and juveniles and physical barriers may be responsible for the current genetic structure.