TITLE:
Phylogenetics and Molecular Divergence of Tilapia Fish (Oreochromis Species) Using Mitochondrial D-Loop and Cytochrome b Regions
AUTHORS:
Ekerette Emmanuel Ekerette, Ekei Victor Ikpeme, Ogbuagu Ugorji Udensi, Michael Ohiokhuaobo Ozoje, Owoidihe Monday Etukudo, Anthony John Umoyen, Samuel Olutunde Durosaro, Matthew Wheto
KEYWORDS:
Phylogenetics, Molecular Divergence, Maternal Lineage, Tilapia Fish
JOURNAL NAME:
American Journal of Molecular Biology,
Vol.8 No.1,
December
28,
2017
ABSTRACT: Understanding the level of genetic diversity in any
population is an important requisite towards strategizing measures for
conservation and improvement of stocks. This study focused on the assessment of
phylogenetics and molecular divergence of tilapia fish species obtained from
two populations (Domita in South-South and Odeda in South-West, Nigeria) using
the displacement loop (D-loop) and cytochrome b region of the mitochondrial
deoxyribonucleic acid (mtDNA). A total of 28 samples (15 from South-South and
13 from South-West) were used for the genetic analysis. DNA was extracted from the
tissue of all the samples using Quik-gDNATM miniPrep kit. The D-loop
containing the hypervariable region was sequenced for all samples from the two
populations, while cytochrome b (Cyt b) region of mtDNA was only sequenced for
samples from South-South population. Chromatograms of the sequences were viewed
and edited using Bioedit software. Multiple sequence alignment was carried out
using molecular evolutionary genetic analysis (MEGA) software before subsequent
genetic analyses. Phylogenetic analysis grouped the samples into two clusters
based on population. Also, when the two mitochondrial regions were pooled
together, they clustered into two major groups based on mitochondrial regions.
Analysis of molecular variance (AMOVA) revealed 37.32% variation within
population and 62.68% variation among population with a significant fixation
index of 0.627 (p 0.05). The genetic distance inferred between D-loop regions of
South-South and South-West populations was 0.243. Maternal lineage analysis
revealed that the origin of tilapia fish from
both populations could be traced to Oreochromis
spirilus and Oreochromis leucostictus based on mitochondrial D-loop region. The findings of this study revealed
molecular divergence among the tilapia populations and may serve as pivot
information for the genetic improvement of this important species.