GENETIC CHARACTERIZATION of HONEYBEE (Apis Mellifera) in COMO- ROS ISLANDS USING MITOCHONDRIAL and MICROSATELLITE MARK- ERS
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GENETIC CHARACTERIZATION OF HONEYBEE (Apis mellifera) IN COMO- ROS ISLANDS USING MITOCHONDRIAL AND MICROSATELLITE MARK- ERS Okwaro Louis Allan (BSc.) I56/34038/2015 A Thesis Submitted in Partial Fulfillment of the Requirements for the Award of the Degree of Master of Science (Biotechnology) in the School of Pure and Applied Sci- ences of Kenyatta University June, 2019 ii iii DEDICATION Dear Dad and Mum, Remember the evenings you narrated folk tales? Yes! You broke them down in such a way that, young as I was, I always got the point. Those early lessons shaped my view of education as a concept of storytelling! Today, I dedicate my story to you. Broken down in a way that old as you may consider yourself, you will get the message. Thank you for having laid a strong foundation and motivating me to achieve the higher heights of educa- tion. It was not easy, but with your support, I moved on. ―Mutio muno‖ ~ Thank you! iv ACKNOWLEDGEMENTS First I thank the almighty God for the good life, health and strength which enabled me do the work with minimal hitches. It is a common say that it takes a village to raise a child. My case is not different. I would like to pass my sincere gratitude to Prof. Raina Suresh and Dr. Elliud Muli for giving me this great opportunity to carry out my research work. I am grateful to my supervisors PD Dr Michael Lattorff, Dr Elliud Muli and Dr Steven Runo for the outstanding mentorship, guidance and support throughout my research work. My sincere appreciation to the International Center of Insect Physiology and Ecology (ICIPE) for having provided me with the research facilities without which this work would not have been possible. More precisely to the International Fund for Agricultural Department (IFAD) and ICIPE‘s Dissertation Research Internship Programme (DRIP) under which I was awarded the scholarship to carry out this work. Many thanks to Ken- yatta University and the department of Biochemistry, Microbiology and Biotechnology where I am registered. I would also like to acknowledge the Kenyatta University Gradu- ate School for proper guidance during my thesis preparation. Lastly, I would like to thank all the members of the African Reference Laboratory for Bee Health for their support, positive criticisms and advice. A special mention to Kelvin Muteru, Joseph Kilonzo, Nelly Ndungu, Pamela Seda, Yoseph Hamba Tola and Gilbert Rotich who were always there to give me support when the going got tough. v TABLE OF CONTENTS DECLARATION .......................................................................... Error! Bookmark not defined. DEDICATION ................................................................................................................................ ii TABLE OF CONTENTS ................................................................................................................ v LIST OF TABLES ....................................................................................................................... viii LIST OF FIGURES ....................................................................................................................... ix ABREVIATIONS ........................................................................................................................... x ABSTRACT ................................................................................................................................... xi CHAPTER ONE ............................................................................................................................. 1 INTRODUCTION .......................................................................................................................... 1 1.1 Background information ....................................................................................................... 1 1.2 Statement of the problem ...................................................................................................... 5 1.3 Justification ........................................................................................................................... 5 1.4 Hypothesis ............................................................................................................................. 7 1.5 Objectives .............................................................................................................................. 7 1.5.1 General objective ............................................................................................................ 7 1.5.2 Specific objectives .......................................................................................................... 7 CHAPTER TWO ............................................................................................................................ 8 LITERATURE REVIEW ............................................................................................................... 8 2.1 Classification of honeybees ................................................................................................... 8 2.2 History and the origin of honeybees ..................................................................................... 9 2.3 Genetic diversity in honeybees and its importance ............................................................. 12 2.4 Characterization of honeybees based on mitochondrial DNA ............................................ 14 2.5 Characterization of honeybees based on microsatellite DNA ............................................. 15 2.7 Hardy Weinberg Equilibrium (HWE) ................................................................................. 19 2.8 Advantage of using GST to determine population differentiation ....................................... 20 CHAPTER THREE ...................................................................................................................... 22 MATERIALS AND METHODS .................................................................................................. 22 3.1 Study site ............................................................................................................................. 22 3.2 Sampling.............................................................................................................................. 22 3.3 DNA Extraction from honeybees ........................................................................................ 25 vi 3.4 Mitotypes of honeybee colonizing the Comoros islands .................................................... 25 3.4.1 PCR amplification of COI-COII intergenic region ...................................................... 25 3.4.2 Agarose gel electrophoresis and sample purification ................................................... 26 3.4.3 Sequencing of the COI-COII intergenic region ............................................................ 27 3.4.4 COI-COII intergenic region sequence analyses ........................................................... 28 3.5 Genetic diversity, population differentiation and population structure............................... 29 3.5.1 Microsatellite DNA amplification ................................................................................ 29 3.5.2 Fragment analysis and allele scoring ............................................................................ 31 3.5.3 Determination of queen mating frequency ................................................................... 32 3.5.4 Prediction of queens using drones ................................................................................ 33 3.5.5 Genetic diversity and linkage disequilibrium ............................................................... 33 3.5.6 Population differentiation and population structure: .................................................... 34 3.5.6.1 Population differentiation ......................................................................... 34 3.5.6.2 Analysis of Molecular Variance (AMOVA) ............................................. 34 3.5.6.3 Population structure .................................................................................. 34 CHAPTER FOUR ......................................................................................................................... 36 RESULTS ..................................................................................................................................... 36 4.1 Mitotypes of honeybee colonizing the Comoros islands .................................................... 36 4.1.1 Amplification of the COI-COII Intergenic Region ...................................................... 36 4.1.2 COI-COII intergenic region sequence analyses ........................................................... 37 4.2 Genetic diversity, population differentiation and population structure............................... 43 4.2.1 Microsatellite DNA amplification ................................................................................ 43 4.2.2 Fragment analysis and allele scoring ............................................................................ 43 4.2.3 Determination of queen mating frequency ................................................................... 44 4.2.4 Prediction of queens using drones ................................................................................ 44 4.2.4.1 Genetic diversity and linkage disequilibrium ........................................... 45 4.2.4.2 Population differentiation and population structure ................................. 51 4.2.4.2.1