Joel Ogwang

Abstract

Since the Suez Canal connected the Red Sea with the Mediterranean, several fish species have migrated between the two seas. Nemipterus randalli has crossed from the Red Sea to the Mediterranean (Lessepsian migration) whereas Serranus cabrilla is considered to have crossed in the reverse direction (anti-Lessepsian migration). Genetic variation between populations of these fish species on either side of the Suez Canal might provide valuable information on their patterns of migration. In this study, 600 bp of cytochrome c oxidase subunit I (COI) sequences were used to compare genetic diversity of populations of N. randalli from the eastern Mediterranean with a population off the Red Sea coast near Hurghada, Egypt. For comparison, three other Nemipterus species were included. Similarly, genetic diversity of Serranus cabrilla from the Gulf of Suez was compared with populations in the eastern Mediterranean Sea. A Maximum Likelihood (ML) tree was constructed using Molecular Evolutionary Genetics Analysis version 7 (MEGA7) software to visualize the evolutionary relationships of S. cabrilla and Nemipterus species of the two seas. Population structures of N. randalli and S. cabrilla were assessed by constructing haplotype networks using PopART. Results from COI sequence divergence analysis revealed possible existence of cryptic species of N. bipunctatus in the Red Sea. Although the ML tree resolved Nemipterus species into four clades representing the four species analyzed, all N. randalli sequences from both seas formed a single clade. Genetic diversity analysis revealed that Mediterranean populations of N. randalli share one haplotype from the Red Sea and supported unidirectional multiple invasion events from the Red Sea to the Mediterranean Sea. Meanwhile, S. cabrilla sequences formed two phylogenetic clades representing the Gulf of Suez and eastern Mediterranean Sea populations. S. cabrilla from the Gulf of Suez also had a significantly reduced sequence divergence compared to Mediterranean Sea populations. In addition, none of the 17 haplotypes in the Mediterranean Sea was found among the 12 haplotypes in the Gulf of Suez. Together, these results provided evidence that the S. cabrilla population in the Gulf of Suez did not come from the Mediterranean Sea through the Suez Canal as was previously thought. According to these results, reported cases of invasion on either side of the Suez Canal should be followed by genetic investigations on a species-by-species basis.

School

School of Sciences and Engineering

Department

Biotechnology Program

Degree Name

MS in Biotechnology

Graduation Date

2-1-2019

Submission Date

1-2-2019

First Advisor

Bos, Arthur R

Committee Member 1

Moustafa, Ahmed

Committee Member 2

Abou-Aisha, Khaled

Extent

63 p.

Document Type

Master's Thesis

Rights

The author retains all rights with regard to copyright. The author certifies that written permission from the owner(s) of third-party copyrighted matter included in the thesis, dissertation, paper, or record of study has been obtained. The author further certifies that IRB approval has been obtained for this thesis, or that IRB approval is not necessary for this thesis. Insofar as this thesis, dissertation, paper, or record of study is an educational record as defined in the Family Educational Rights and Privacy Act (FERPA) (20 USC 1232g), the author has granted consent to disclosure of it to anyone who requests a copy.

Institutional Review Board (IRB) Approval

Not necessary for this item

Comments

My supervisor, Dr. Arthur Bos was immensely supportive from the inception of this project and his effort never wavered at any point. Dr. M. Bariche (AUB) contributed samples from Lebanon. Dr. Ahmed Moustafa (AUC) provided invaluable support in the initial molecular analyses of this work. Mr. Amged Aouf (AUC) provided initial technical input to kick-start this project and handled most procurement related to this work. The laboratory attendants, Zain and Mohamed were immensely helpful. My friends offered a helping hand in the lab: Youssef, Mariam, Muziri, Eric Zadok, Yomna Moqidem, to mention a few. I am also grateful to the African Graduate Fellowship for the opportunity to conduct my graduate study in AUC. Finally, this work would have been impossible without the AUC Graduate Research Grant.

Creative Commons License

Creative Commons Attribution-NonCommercial 4.0 International License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License

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