<P> Mitochondria contain DNA which is distinct from nuclear DNA. The capacity of isolated rat liver mitochondria to synthesize RNA and the types of RNA synthesized were examined in order to determine the genetic function of mitochondrial DNA. </p> <p> It was demonstrated that isolated rat liver mitochondria synthesize RNA, incorporating [3H]UTP, [3H] ATP,[3H]CTP and [3H]GTP in a DNA-dependent reaction. In addition, the DNA-independent incorporation of [3H]CTP and [3H]ATP suggested metabolic turnover of the CCA end of mitochondrial tRNA. </p> <P> Analysis of the , newly-synthesized RNA by sucrose density gradient centrifugation and agarose-polyacrylamide gel electrophoresis demonstrated that mitochondrial ribosomal RNA was synthesized in a DNA-dependent process. It is concluded that one of the genetic functions of mitochondrial DNA is to code for mitochondrial ribosomal RNA. </p> / Thesis / Doctor of Philosophy (PhD)

>Magister Scientiae - MSc / Bladder grasshoppers belong to the order Orthoptera, ancient family Pneumoridae and Superfamily Pneumoroidea. This small group of grasshoppers are sound producing, nocturnal, herbivorous grasshoppers endemic to the coastal regions of southern Africa. Very little genetic work has been done on these grasshoppers, and there is some taxonomic confusion regarding the validity of some species descriptions. The aim of this study was to provide much needed clarity on the true taxonomic diversity and polymorphic attributes within the Pneumoridae, focusing on selected taxa of uncertain status. Bladder grasshoppers show distinct discontinuous polymorphism, resulting in two clearly different male morphs utilizing two different mating strategies. Primary males make use of acoustic communication for mate location. Secondary males (alternate males) are significantly smaller and employ a “sneaker” or satellite strategy where they exploit the calling between duetting couples to locate the females before the primary male. Three species of bladder grasshoppers have been described (Parabullacris vansoni, Paraphysemacris spinosus and Pneumoracris browni) that only have an alternate male morph. The validity of these species descriptions has come into question with the discovery of alternate male morphs in at least three other species (Bullacris discolor, B. membracioides and B. obliqua). Thus, the species described by Dirsh (1963) may simply be alternate males of existing species. However, to date there have been no studies looking at the genetics of alternate males, which would definitively establish whether they are conspecific with primary males.

Biogeographers have long searched for common processes responsible for driving diversification in the Holarctic region. Although terrestrial flora and fauna have been well studied, much of the marine biogeographic work addresses patterns and processes occurring over a relatively recent timescale. A prerequisite to comparative biogeographic analysis requires well-resolved phylogenies of similarly distributed taxa that diverged over a similar timeframe. The overall aim of my Ph.D. thesis was to address fundamental questions in the systematics and biogeography of a family of Holarctic fish (Osmeridae) and place these results in a broad comparative biogeographic framework. With eight conflicting morphological hypotheses, the northern hemisphere smelts have long been the subjects of systematic disagreement. In addition to the uncertainty in the interrelationships within this family, the relationship of the Osmeridae to several other families remains unclear. Using DNA sequence data from three mitochondrial and three nuclear genes from multiple individuals per species, I reconstructed the phylogenetic relationships among the 6 genera and 15 osmerid species. Phylogenetic reconstruction and divergence dating yielded a well-resolved phylogeny of the osmerid genera and revealed several interesting evolutionary patterns within the family: (1) Hypomesus chishimaensis and H. nipponensis individuals are not reciprocally monophyletic, suggesting that they are conspecific and H. chishimaensis is a recently evolved freshwater ecotype that invaded the Kuril Islands following the last glaciation, (2) The trans-Pacific sister relationships in Hypomesus based on lateral line scale counts are not supported, implying that this phenotype evolved in parallel on each side of the North Pacific Ocean, (3) The Plecoglossidae are the Osmeridae sister group, (4) Over half of the characters from previous studies show evidence of parallel evolution; however, 27 traits reflect ancestral relationships, (5) Multiple divergences within the Osmeridae date to both the mid-Miocene cooling period and the Pliocene Bering Seaway opening, suggesting these events were important in the evolution of these fishes, and (6) Divergences in many marine taxa for which dated phylogenies are available are also correlated with these time periods. Future research should target additional Holarctic marine taxa for further comparative analysis.

Members of the family Placobranchidae have been the focus of numerous studies because of their interesting physiological adaptations (kleptochemistry and kleptoplasty) and ecological associations with marine algae. More than 100 species have been described since the 1800's, but no determination of phylogenetic relationships in the family has occurred. DNA sequences from two mitochondrial genes (large subunit ribosomal and cytochrome c oxidase subunit I) and one nuclear gene (Histone 3) were used to reconstruct relationships among 34 nominal species within the Placobranchidae. Strong support for terminal nodes was found using Bayesian phylogenetic methods; however, a "soft" polytomy was detected at internal nodes. In general, the results confirm the paraphyly of Elysia. Proposals for the designation of the genera, Thallepus Swainson, 1840 and Tridachia Deshayes, 1857 and delineation of species are presented. How intrinsic factors affect speciation rates in groups of animals has been a central focus in evolutionary biology. Adaptive radiation associated with food choice has been postulated for the opisthobranch order Sacoglossa. An increase in the rate of cladogenesis was detected within the family Placobranchidae and intrinsic factors such as larval development, kleptoplasty and food choice were investigated as potential key innovations. Ancestral state reconstruction of characters suggests that food choice played a dominant role in influencing speciation rate within the family Placobranchidae. Life history strategy may play an important role in structuring genetic variation throughout the geographic range of a species. Members of the sacoglossan family Placobranchidae Gray, 1840, exhibit variation in life history strategies such as feeding preference and degree of kleptoplasty that could be influential in population structuring. Three species, Elysia subornata Verrill, 1901, Elysia tuca Marcus and Marcus, 1967, and Elysia crispata Mörch, 1863 were sampled from several locations in an attempt to quantify genetic variation as indicated by cytochrome c oxidase subunit I gene sequencing. Elysia crispata exhibited the highest degree of population subdivision followed by Elysia tuca and Elysia subornata. Nucleotide and haplotype diversity also revealed the same general ranking of species. Preliminary conclusions suggest that diversity in feeding preference and degree of kleptoplasty play significant roles in population subdivision of these species.

Biogeographers have long searched for common processes responsible for driving diversification in the Holarctic region. Although terrestrial flora and fauna have been well studied, much of the marine biogeographic work addresses patterns and processes occurring over a relatively recent timescale. A prerequisite to comparative biogeographic analysis requires well-resolved phylogenies of similarly distributed taxa that diverged over a similar timeframe. The overall aim of my Ph.D. thesis was to address fundamental questions in the systematics and biogeography of a family of Holarctic fish (Osmeridae) and place these results in a broad comparative biogeographic framework. With eight conflicting morphological hypotheses, the northern hemisphere smelts have long been the subjects of systematic disagreement. In addition to the uncertainty in the interrelationships within this family, the relationship of the Osmeridae to several other families remains unclear. Using DNA sequence data from three mitochondrial and three nuclear genes from multiple individuals per species, I reconstructed the phylogenetic relationships among the 6 genera and 15 osmerid species. Phylogenetic reconstruction and divergence dating yielded a well-resolved phylogeny of the osmerid genera and revealed several interesting evolutionary patterns within the family: (1) Hypomesus chishimaensis and H. nipponensis individuals are not reciprocally monophyletic, suggesting that they are conspecific and H. chishimaensis is a recently evolved freshwater ecotype that invaded the Kuril Islands following the last glaciation, (2) The trans-Pacific sister relationships in Hypomesus based on lateral line scale counts are not supported, implying that this phenotype evolved in parallel on each side of the North Pacific Ocean, (3) The Plecoglossidae are the Osmeridae sister group, (4) Over half of the characters from previous studies show evidence of parallel evolution; however, 27 traits reflect ancestral relationships, (5) Multiple divergences within the Osmeridae date to both the mid-Miocene cooling period and the Pliocene Bering Seaway opening, suggesting these events were important in the evolution of these fishes, and (6) Divergences in many marine taxa for which dated phylogenies are available are also correlated with these time periods. Future research should target additional Holarctic marine taxa for further comparative analysis.

The number of non-parasitic (brook) lamprey species in the genus Lampetra is underestimated since isolated populations are generally considered one species due to their relatively conserved body form. The phylogeographic and phylogenetic structure was estimated among and within Lampetra species along the Pacific coast of North America (presumed to represent Lampetra richardsoni; L. pacifica – which is currently regarded as a junior synonym of L. richardsoni; L. ayresii; and L. hubbsi) using up to three mitochondrial and three nuclear genetic markers. These data show that L. richardsoni as currently recognized is polyphyletic when lampreys (some of which show up to 8 K2P% sequence divergence) from Siuslaw River and Fourmile Creek (Oregon) and Mark West, Paynes, and Kelsey creeks (California) are included; Lampetra pacifica is a valid species; the population from Kelsey Creek almost certainly represents a new species; and those from Siuslaw, Fourmile, and Mark West may also be distinct species.

The number of non-parasitic (brook) lamprey species in the genus Lampetra is underestimated since isolated populations are generally considered one species due to their relatively conserved body form. The phylogeographic and phylogenetic structure was estimated among and within Lampetra species along the Pacific coast of North America (presumed to represent Lampetra richardsoni; L. pacifica – which is currently regarded as a junior synonym of L. richardsoni; L. ayresii; and L. hubbsi) using up to three mitochondrial and three nuclear genetic markers. These data show that L. richardsoni as currently recognized is polyphyletic when lampreys (some of which show up to 8 K2P% sequence divergence) from Siuslaw River and Fourmile Creek (Oregon) and Mark West, Paynes, and Kelsey creeks (California) are included; Lampetra pacifica is a valid species; the population from Kelsey Creek almost certainly represents a new species; and those from Siuslaw, Fourmile, and Mark West may also be distinct species.

Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv & Cons Biol) / Salicornia tegetaria is an endemic salt marsh macrophyte that is widely distributed in estuaries along the South African coast. The aims of the study were to understand the phylogeography of the species, compare the biomass allocation in two regions and to determine phenological patterns of S. tegetaria between the warm and cool temperate biogeographical regions. The phylogeography of S. tegetaria was studied using the noncoding chloroplast DNA region rpS16 and nuclear rDNA ITS region. Five samples each were collected from eighteen estuaries stretching from Orange River in the Northern Cape to Mngazana Estuary in the Eastern Cape. Above- and belowground biomass was collected and physico-chemical conditions measured at Olifants, Berg and Langebaan Estuaries in the cool temperate, and Heuningnes, Nahoon and Kwelera Estuaries in the warm temperate biogeographical regions. The growth and flowering phenology of S. tegetaria in relation to environmental conditions was investigated in the cool temperate Langebaan Estuarine Embayment and compared to findings in the warm temperate, permanently open Kowie Estuary. The physico-chemical gradient found between the cool and warm temperate biogeographical regions may be useful to study climate change effects on plant species. The comparison of similar habitats in each region may provide insight into how different climate regimes may affect biomass allocation and phenology.

Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv & Cons Biol) / Salicornia tegetaria is an endemic salt marsh macrophyte that is widely distributed in estuaries along the South African coast. The aims of the study were to understand the phylogeography of the species, compare the biomass allocation in two regions and to determine phenological patterns of S. tegetaria between the warm and cool temperate biogeographical regions. The phylogeography of S. tegetaria was studied using the noncoding chloroplast DNA region rpS16 and nuclear rDNA ITS region. Five samples each were collected from eighteen estuaries stretching from Orange River in the Northern Cape to Mngazana Estuary in the Eastern Cape. Above- and belowground biomass was collected and physico-chemical conditions measured at Olifants, Berg and Langebaan Estuaries in the cool temperate, and Heuningnes, Nahoon and Kwelera Estuaries in the warm temperate biogeographical regions. The growth and flowering phenology of S. tegetaria in relation to environmental conditions was investigated in the cool temperate Langebaan Estuarine Embayment and compared to findings in the warm temperate, permanently open Kowie Estuary. The physico-chemical gradient found between the cool and warm temperate biogeographical regions may be useful to study climate change effects on plant species. The comparison of similar habitats in each region may provide insight into how different climate regimes may affect biomass allocation and phenology.

Submitted by Katiane Souza (katyane.souza@gmail.com) on 2016-06-05T16:57:52Z No. of bitstreams: 1 arquivototal.pdf: 2970217 bytes, checksum: d54e4990a98e77a7f5d22ad2384ffdd3 (MD5) / Made available in DSpace on 2016-06-05T16:57:52Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2970217 bytes, checksum: d54e4990a98e77a7f5d22ad2384ffdd3 (MD5) Previous issue date: 2015-12-10 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The subtribe Laeliinae comprises about 2000 species in 38 genera, exclusively neotropical and is considered the third largest family of subtribe. Cytological features most species with basic chromosome number x = 20 and karyotype evolution mainly associated with polyploidy. This study aimed performed a comparative cytogenetic analysis in 42 species of Laeliinae subtribe based on banding fluorochromes with CMA/DAPI, and estimate the nuclear DNA content of many of these species through citmetria of flow. All species presented 2n = 40 except Cattleya nobilior with 2n = 42 and the polyploid C. elongata, C. crispata, Encyclia alboxanthina, E. jenischiana, E. seidelii, Laelia gouldiana and Prosthechea faresiana (2n = 80). We observed two blocks CMA+/DAPI terminals in all species. The DNA content of species ranged from 2C = 3.45 pg in Brassavola nodosa to 2C = 7.96 pg in C. guttata. The leaf tissues of the analyzed representatives presented endoreduplication cycles in most species. Our data suggest that although it occurs an apparent macrostructural stable karyotype (2n = 40) in the species of the subtribe Laeliinae as well as the genus Cattleya studied, they present a pattern of diversification of heterochromatin consistent with the phylogenetic clusters and identify possible sinapomorphies that allow better understanding of taxonomically complex species. / A subtribo Laeliinae compreende cerca de 2000 espécies distribuídas em 38 gêneros, exclusivamente neotropical, sendo considerada a terceira maior subtribo da família. Citologicamente apresenta a maioria das espécies com número cromossômico básico x = 20 e evolução cariotípica principalmente associada a poliploidia. O presente trabalho objetivou realizada uma análise citogenética comparativa em 42 espécies da subtribo Laeliinae com base em bandeamento com fluorocromos, CMA/DAPI, além de estimar o conteúdo de DNA nuclear de várias dessas espécies através de citometria de fluxo. Todas as espécies apresentaram 2n = 40, exceto Cattleya nobilior com 2n = 42 e os poliploides C. elongata, C. crispata, Encyclia alboxanthina, E. jenischiana, E. seidelii, Laelia gouldiana e Prosthechea faresiana (2n = 80). Foram observados pelo menos dois blocos CMA+/DAPI terminais em todas as espécies, além de bandas DAPI+/CMA– proximais ou terminais em várias outras espécies. O conteúdo de DNA das espécies variou de 2C = 3,45 pg em Brassavola nodosa até 2C = 7,96 pg em C. guttata, com ciclos de endoreduplicação na maioria das espécies. Nossos dados sugerem que embora ocorra uma aparente estabilidade cariotípica macroestrutural (2n = 40) nas espécies da subtribo Laeliinae e no gênero Cattleya como um todo, em geral, o padrão de diversificação da heterocromatina foi compatível com os agrupamentos filogenéticos, identificando possíveis sinapomorfias que permitem um melhor entendimento de espécies taxonomicamente complexas.