English

I A Taiwo,O R Oguntade,A B Usman,E A Ukenye,T O Oketoki

doi:10.5897/ajb2015.14599

Abstract

Tilapia guineensis is an important economically and nutritionally important fish commonly found in Nigerian coastal waters. Genetic diversity of the fish was assessed to obtain information that may help in developing appropriate conservation and breeding programmes for improving the economic and nutritional quality of the fish. Twelve (12) Nigerian coastal populations and nine microsatellite loci were considered. All the loci were multi-allelic giving an average of 3.1 alleles per locus. The number of alleles (Na) ranged from two to four alleles per locus while the effective number of expected alleles (Ne) ranged from 1.087 to 2.612. Buguma, Badagry and Brass populations had the highest genetic diversity as was revealed by heterozygosity (observed and expected) and shannon index of the populations. The longest pairwise genetic distance of 0.30 was between Brass in Bayelsa State and River Ethiope in Delta State. Clustering using simple sequence repeat (SSR) data gave four major clusters which did not concur with geographical location clustering. We conclude that although genetic diversity is low in some populations of T. guineensis in Nigerian coastal waters, some populations (Buguma, Badagry and Brass) still retain some genetic variability which may be explored for fish improvement through appropriate breeding and conservation programmes.     Key words: Molecular characterization, genetic diversity, microsatellite analysis, Tilapia guineensis, coastal rivers. &nbsp

Highlights

Tilapia guineensis is one of the most important Cichlid species, in view of its nutritional role in many tropical and sub-tropical countries (Saisithi, 1994)
We conclude that genetic diversity is low in some populations of T. guineensis in Nigerian coastal waters, some populations (Buguma, Badagry and Brass) still retain some genetic variability which may be explored for fish improvement through appropriate breeding and conservation programmes
All nine microsatellite loci were polymorphic in all populations (Figure 2) with polymorphic information content (PIC) values ranging from 0.07 at locus GM211 to 0.54 at locus UNH207 with an average of 0.31 (Table 3)

Summary

Introduction

Tilapia guineensis is one of the most important Cichlid species, in view of its nutritional role in many tropical and sub-tropical countries (Saisithi, 1994). It is an important source of animal protein and income throughout the world especially in developing countries like Nigeria with many rural populations relying on subsistent farming (Sosa et al, 2005). The species is usually found in creeks, lagoons and other coastal waters of West Africa (Philippart and Ruwet, 1982) It shows good aquaculture potential and has been successfully raised in ponds, enclosures, cages and tanks. Despite the nutritional and economic importance of T. guineensis worldwide, our knowledge of the genetic status in terms of genetic diversity of its natural populations is still inadequate for sustainable aquaculture practices, conservation and improvement through selective breeding (Agenes et al, 1999)

Methods

Results

Conclusion