INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter ftice. while others may t>e from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print t)leedthrough, substarxJard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to t>e removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Photographs included in the original manuscript have t)een reproduced xerographically in this copy. Higher quality 6" x 9” black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. Bell & Howell Information and Learning 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 800-521-0600 UMI* GENETIC BIODIVERSITY AND EVOLUTION OF TWO PRINCIPAL FISHERIES SPECIES GROUPS, THE LABEINE AND TILAPHNE, OF LAKE VICTORIA REGION, EAST AFRICA DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University BY Wilson Waiswa Mwanja, B.Sc., M.S., PGDE, Cert. Limn. ***** The Ohio State University 2000 Dissertation Committee: AppFQved by Professor Paul A. Fuerst, Adviser i2Q. Professor Ted Cavender Adviser Associate Prof. Allison Snow Evolution, Ecology and Organismal Biology Associate Prof. Patricia E. Parker Graduate Program UMI Number 9962435 UMI UMI Microform9962435 Copyright 2000 by Bell & Howell Information and beaming Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. Bell & Howell Information and beaming Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 ABSTRACT The study sought to establish the genetic status of the remnant populations of the two original native principal commercial species in the Lake Victoria Region; the tilapiine species that formed the basis of the lacustrine fishery; and the labeine, namely Labeo victorianus, that formed the basis of the riverine fishery. The genetic status of the two the two groups were contrasted and compared with the introduced congeners in the Lake Victoria region in case of tilapiine species and to the congeners from the neighboring waters outside Lake Victoria Region for the labeine, Labeo victorianus. The study investigated the general hypothesis that the introduction of non-indigenous species and recent limnological changes that have taken place in the various water bodies of Lake Victoria region resulted not only in ecological marginalization but also led to the depletion of the genetic diversity of the native species. The genetic structures of the remnant populations of the native species and the established populations of the introduced non-indigenous congeners were contrasted using molecular analysis. RAPD analysis was used for L. victorianus while both the RAPD and microsatellite analyses were used for the tilapiine species. Among Labeines, the only recorded native species in Lake Victoria and Lake Kyoga basins of the LVR, Labeo victorianus, showed no genetic depletion compared to its congeners. L. victorianus populations were highly subdivided but with relatively polymorphic populations. 63.6% of the RAPD marker variation was found to occur among populations compared to 34.4% within-populations. As a species, L. victorianus had more private alleles than either congeners or the characid and barbine (used as outgroups in the phyletic analysis of the remnant population relative to congeners). L. victorianus exhibited molecular variation equal to or more than that of its congeners. Among tilapiines the introduced tilapiine species, Oreochromis niloticus, the ecologically most dominant tilapiine in the region, was the most genetically variable and least subdivided. Oreochromis leucostictus, another of the introduced Oreochromis species, was the second to O. niloticus in variability but had the highest gene flow amongst its populations. The high migration rate was linked to the ability for O. leucostictus to traverse swamps better than the other tilapiine species in the region. The two native tilapiine species, Oreochromis esculentus and Oreochromis variabilis, were the least variable except in cases were the populations were coexisting with the introduced congeners. Populations of O. esculentus from Nabugabo lakes. Lake Kayanja, Lake Kayugi, and Lake Manywa, and one from Lake Kawi among Kyoga lakes were foimd to be the only extant ‘pure’ forms of this species in the wild. Among the O. variabilis populations there were no discernable patterns of differentiation by Lake Systems or sub systems as in other Oreochromis species. O. variabilis populations were apparently swamped by O. niloticus like alleles, and were found to be highly differentiated as independent units, and had the least gene flow between sub-populations. Among the populations of Tilapia zilli, originally most prevalent and widespread at the time of introduction, the species was sparse and restricted in distribution. The species was found to genetically highly subdivided, but with high within population genetic variation. The high within population genetic variation, despite the high differentiation among populations, was linked to genetic interaction with Tilapia rendalli, another of the introduced species. The results showed that there was genetic interaction between the introduced and the native species. Genetic swamping of the remnant native populations by the introduced species, especially by O. niloticus over the two native species was a major force in marginalization of the remnant native populations. On a macroevolutionary level our results fcimd the sister relationship between O. niloticus and O. esculentus questionable and in need of further phylogenetic analysis. The results justify a necessity for adopting molecular markers in monitoring changes in the fishery, as in many species in the region, including some of the introduced commercial species, face similar predicaments. IV To Samwiri K. Mwanja and Edisa Kinawa Nabirye ACKNOWLEDGMENTS I am highly indebted to Professor Paul Fuerst for giving me the chance to study evolutionary genetics and conservation biology in his laboratory for the past six years. I am grateful for his funding of my studies, but most important for guiding me through quite a challenging area of study in an evolutionary interesting and unique biogeographic Lake Victoria region system, and oceans away from Columbus Ohio. I am grateful to my graduate studies committee. Professors Ted Cavender, Allison Snow and Patricia Parker, for their guidance, advice and the time they put in shaping my ideas and helping me in my approach to this dissertation. I am grateful to Dr. Les Kaufman of Boston University, for the interaction, advice and training he offered me during the course of my graduate studies. His advice and exchange greatly enriched my science foundation and gave me a deeper meaning and understanding of the need to conserve nature in general. My studies at Ohio State University started with the invitation from a stranger at the time, in the hallways of the Agriculture faculty at Makerere University, Professor David Hansen. Dave suggested that I should consider working with Professor Paul Fuerst on Lake Victoria fishes since I was interested in Fish Genetics, the choice that turned out to right and great for me. I am very grateful to Professor David Hansen, Dr Mark Erbaugh, James Haldeman, Francine Jasper and all those who were involved with the Agriculture Research Training Program, through your efforts, my experience at Ohio State University was rich, wonderful and productive. I am highly indebted to the best Secretary I have known, Mrs Jessica L. Siegman and vi her colleague Marsha K. Hronek - their secretarial services and adminstration in Molecular Genetics Department made stay in the Biological Sciences College and the graduate school academically satisfying and comfortable. This work was made possible by facilitation and advice from Dr. Ogutu- Ohwayo, Dr. John Balirwa, Dr. Fred Bugenyi, Mr. Sylvester Wandera and Mr. John Kamanyi of the Fisheries Research Institute (FIRI) at Jinja in Uganda; and Mr. Andrew Asila and Joseph Mwangi of Kenya Marine and Freshwater Fisheries Research Institute (KMFRI). I am indebted to my Lab colleagues for the exchanges we had, advice they gave me, and training, especially in molecular methods, over the course of my time in Professor Paul Fuerst's laboratory. I am especially grateful to Dr. Gregory Booton, Dr. Malcomb Schug, Dr. Porter Brady, Dr. Lizhao Wu, Dr. Jeannette Krieger and Dr. Wenrui Duan, all graduates from Professor Paul Fuerst’s lab since I joined in 1993. Their time and generosity greatly enriched my evolutionary genetics background. I would like to thank my field work crew, including Mr. Bob Amina, ‘Dr.’ All Katende, Mr. John Magezi, Mr. Fred Mugume, Mr. Brian Ddungu; and my research assistants in the