ASSESSMENT OF GENETIC VARIATIONS IN Pomadasys jubelini POPULATIONS FROM HIGH AND LOW BRACKISH LAGOONS USING RANDOMLY AMPLIFIED POLYMORPHIC DNA ANALYSIS TECHNIQUE  

Olufemi O. Soyinkaa*and Abduwakil O. Sabaa
aDepartment of Marine Sciences, University of Lagos, Lagos, Nigeria
*Correspondence author: Email- soyinka.olufemi@gmail.com

Genetic relationship of Grunter, Pomadasys jubelini, populations from high brackish lagoon (Lagos Lagoon) and low brackish lagoon (Badagry Lagoon) using randomly amplified polymorphic DNA analysis technique was studied using two 10-mer OPAS primers to assay polymorphisms between the two populations. Only one of the primers produced distinct and consistent RAPD profiles. Mean DNA yield and purity were 133.52 ± 41.4ng/µl and 1.68 ± 0.74 from Lagos Lagoon and 168.4 ± 41.24ng/µl and 1.69 ± 1.78 from Badagry Lagoon specimens. Thirty six reproducible bands and slight DNA polymorphism (20%) was found in populations from both locations. Cluster analysis gave no sufficient genetic divergence to discriminate the samples.

Samples of Pomadasys jubelini were collected from Lagos and Badagry Lagoons, south-west Nigeria. Extraction of Genomic DNA was done using a salting out protocol described by Miller et al. (1988). Assessment of DNA yield and purity was measured using a nanodrop spectrophotometer (NANO 1000, China) based on maximum absorbance of DNA at 260 nm. RAPD-PCR Amplification reaction was performed. Agarose gel was prepared. Reactions were performed following a strict protocol with standardized conditions. The products were analyzed using Phyllip software (version 2.1, USA). Gels were scored for the presence or absence of amplicon in each lane. Only the reproducible and intense bands ranging from 400 to 1200 bp were scored to maintain the consistency across the samples. Dendrogram was created using arithmetic (UPGMA) average clustering. Images of gels were used to analyze banding patterns.

Purity of DNA ranged between 1.68 and 1.75.  Therefore, the samples were in pure condition without contamination of protein and RNA. A total of 36 reproducible bands were obtained (Plate 1). The present study revealed a low variation of polymorphic (20%) loci between the two populations. Cluster analysis separated the grunters into three major clusters (Figure 1) which consisted of minor clusters at various degree of co-efficient phylogenetic analysis.  The first cluster consists of GL1 and GB3, the second cluster consists of GL4 and GB2 while the third cluster consists of GL2, GB4, GB1 and GB3.