Lizards (Squamata: Lacertidae) and the Evolution of Unisexuality
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PHYLOGENYOF UCERTIDLIZARDS (SQUAMATA:LACERTIDAE) AND THE EVOLUTIONOF UNISEXUAL]CTY Jinzhong Fu A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Graduate Department of Zoology University of Toronto O Copyright by Jinzhong Fu 1999 National Library Bibliothbque nationale la of.,, du Canada Acquisitions and Acquisitions et Bibliographic Services services bibliographiques 395 Wellington Street 395, nre Wellington OttawaON KlAON4 Ottawa ON KIA ON4 Canada Canada your Me votm rdrnrellw Our W Notre rdfdrence The author has granted a non- L'auteur a accorde une licence non exclusive licence allowing the exclusive pennettant a la National Library of Canada to Bibliotheque nationale du Canada de reproduce, loan, distribute or sell reproduire, preter, distribuer ou copies of this thesis in microform, vendre des copies de cette these sous paper or electronic formats. la forme de microfiche/film, de reproduction sur papier ou sur format electronique. The author retains ownership of the L'auteur conserve la propriete du copyright in this thesis. Neither the droit d'auteur qui prothge cette these. thesis nor substantial extracts fiom it Ni la these ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent &re imprimes reproduced without the author's ou autrement reproduits sans son pexmission. autorisation. Phylogeny of Lacertid Lizards (Squamata: Lacertidae) and the Evolution of Unisexuality Doctor of Philosophy Degree, 1999 Jinzhong Fu Department of Zoology The University of Toronto ABSTRACT An overall phylogeny of the Family Lacertidae was inferred fiom a parsimony analysis, using DNA sequence data fiom six mitochondrial genes. A total of 3 1 lacertid species were included, which represented most of the main lineages. The iacertids grouped into two clades, which correspond to the current subfamilies Lacertinae and Gallotiinae. The Lacertinae was further divided into two groups, the African and Eurasian groups. The relationships within the two groups were largely unresolved despite the large number of informative characters. A recent explosive speciation hypothesis was invoked to explain the lack of resolution from this analysis. The ancestors of the African and Eurasian groups experienced multiple simultaneous speciation events which left few or no fixed characters on the internodes making the phylogenetic reconstruction difficult. A special phenomenon, unisexuality, in lacertids was closely examined. A parsimony analysis of DNA sequence data from four mitochondrial genes was conducted to establish a firm phylogenetic foundation for the Caucasian rock lizards, among which the unisexual lacertids originated fiom interspecific hybridization. All bisexual species clustered into three major clades. The hybridization that led to unisexuals were of inter-clade and only occurred between the caucasica and the rudis clades. Moreover, these hybridization events are directional: the caucasica group only contributed to maternal parents while the rudis group to paternal parents. The formation of unisexuality is clearly under phylogenetic constraints. The causative agents of the constraints are likely multi-functional complexes, although sex chromosomes may play an important role. The divergence of cytochrome-b and ATPase 6 genes in the maternal parental species, Lacerta raddei and L. mixta, as we11 as all seven known unisexual daughter species was investigated. All unisexuals constantly showed very little or no variations comparing to the substantial divergence in L. raddei, but L. mixta showed little variation as well. A phylogeny of the mtDNA haplotypes inferred from parsimony analysis suggested that some unisexual species (clones) from the same parents shared a common ancestor while others did not. The formation of unisexual species in lacertids involved single origin, multiple origin with closely related females, as well as rnuItiple origin with distantly related females. ACKNOWLEDGMENTS The five wonderfhl years at the Royal Ontario Museum and University of Toronto put me in deep debt to many people. My gratehlness is far beyond the ability of words. First, I would like to thank Dr. Bob Murphy, my supervisor and friend, offered me this great opportunity to join his team. His friendliness, accessibility, and stimulating talks make him the best supervisor I have ever known. Without his encouragement and support over the years, the work presented in this thesis could not have been done. I am also grateful to the other members of my supervisory committee, Dr. Dan Brooks, and Dr. Hans Sues, for their friendly and stimulating advice and assistance, and critical reading of drafts of the thesis. Thanks also to Dr. Kathy Coates for her support of my first year at U of T. There are four other people I feel greatly indebted. They are Darlene Upton, Ross MacCulloch, Amy Lathrop, and Raoul Bain. Darlene led me into the wonders of the DNA world, starting with what is a primer; Ross trained me in allozyme electrophoresis, and he has always been the "grammar checker" for my publications. Amy, Raoul and I have been squeezed into a small office for the last two and half years. I have benefited huge from the numerous talks and chats, not only academically but culturally as well. I will never forget the blending of phylogenetics, music, and movies. I specially thank Amy for her devotion to herpetology which will always be a model for me to follow. Many thanks also to Oliver Haddrath for his kind help and assistance in the lab. Many other CBCB staff members, as well as other graduate students who have offered their hands to me from time to time. Thank you all. I specially thank to Dr. Ilya Darevsky, who have heIped me in many respects from teaching me how to noose a lizard to checking many data collected from Russian literature. Many ideas presented in this thesis were fostered by the discussion with him. For field assistance, I also thank to F. Danielyan, M. Bakradze, V. Negrnedzanov, and B. Tuniyev. I thank Dr. D. Good, Dr. R. Drewes, Dr. J. V. Vindum, Dr. V. M. Cabrera, Dr. S. D. Busack, Dr. D. J. Harris, and Dr. 0.J. Arribas for generously providing tissue samples. It is by their offer that I have been able to complete this study. Import permits for frozen tissues and preserved specimens were issued by Agriculture Canada. This study was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada grant A3148 to R. W. Murphy. Laboratory work was carried out in the Laboratory of Molecular Systematics of the ROM. TABLE OF CONTENTS .. Abstract ..............................................................................................................................u Acknowledgments ............................................................................................................. iv List of Tables ............................................................................................................................x List of Figures......................................................................................................................... xii List of Appendices ................................................................................................................. xiv Chapter 1. Introduction.................................................................................................... 1 The family Lacertidae ..................................................................................................... 1 The Caucasian rock lizards and the unisexuality ............................................................. 7 Objectives ..................................................................................................................... 1 5 Methods........................................................................................................................ 1 5 Mitochondria1 DNA genetics ........................................................................................ 16 Organization of the dissertation ................................................................................ 17 Chapter 2. Toward the Phylogeny of the Family Lacertidae - Why 4. 708 Base Pairs of mtDNA Sequences Cannot Draw the Picture .................................... 1 8 Abstract ........................................................................................................................1 8 Introduction ..................................................................................................................19 Materials and Methods ................................................................................................ 2 0 Specimens examined .........................................................................................2 0 Genes selected ......................................................................................................... 2 0 Amplification and sequencing protocols .................................................................. 25 DNA alignment.................................................................................................... 26 Phylogenetic anatysis .............................................................................................. 2 6 Results ......................................................................................................................... 30 COI and Cyt-b ........................................................................................................ 30 12s and 16s ............................................................................................................43