Phylogeography of the southern African vlei rat, Otomys irroratus, inferred from chromosomal and DNA sequence data

Thesis (MSc)--University of Stellenbosch, 2010.ENGLISH ABSTRACT: This study examines the phylogeography of the southern African vlei rat, Otomys irroratus using the mtDNA cyt b gene and chromosomal data derived using G-, and C-banding, Ag-NOR staining and fluorescence in situ hybridization (FISH using flow sorts of Myotomys unisulcatus). A total of N = 102 specimens were used from the Western Cape, Eastern Cape, Northern Cape, Free State, Mpumalanga and KwaZulu-Natal provinces of South Africa. Of the N = 102, N = 55 comprised fresh material while N = 47 comprises museum material obtained from the Durban Natural Science Museum of South Africa. Cytogentic analysis of N = 55 specimens collected from seven localities in South Africa revealed intra-specific variation resulting from two rearrangements, namely pericentric inversions and heterochromatin variation. Of the 55 specimens that were analyzed 47% contained inversions or centromeric shifts on four autosomes (OIR1, OIR4, OIR6 and OIR10) which were present singly in specimens (i.e. none of the specimens contained all four inversions concurrently). These inversions were present in both homozygous and heterozygous state over a wide geographic range suggesting that they are floating polymorphisms. Given the potential role of inversions in post-mating isolation (through production of aneuploid gametes), the prevalence of inversions as floating polymorphisms in the vlei rats suggest that they are probably retained in the population through suppression of recombination in the inverted regions of the chromosomes. In addition, differences between populations is due to the presence or absence of heterochromatic arms (and not inversions), which cause variation in the NFa (40 – 49) and supernumerary B chromosomes, resulting in the variation in diploid number (2n = 28 – 32). Analysis of N = 55 specimens revealed Ag-NORs on 7 autosomal pairs 1, 2, 5, 7, 8 and 9 proximal to the centromere on the short arm of the chromosome. Pair 8 also displayed Ag-NOR at the distal end of the long arm of the chromosome in individuals from the Free State province. Pair 3 showed two Ag- NORs occurring proximal to the centromere on the short arm and on the terminal end of the long arm, respectively. I obtained 953bp of mtDNA cyt b from fresh material and 400bp from museum material. Using maximum parsimony and Bayesian inference two main clades were retrieved. Clade A specimens occur mainly in the Western and Eastern Cape provinces of South Africa. Clade B specimens occur in the Eastern Cape, Free State, KwaZulu-Natal, Northern Cape and Mpumalanga provinces of South Africa. The mean sequence divergence between the main clades (A and B) is 7.0% and between sub-clades comprising clade B is 4.8%, while within clade A the sequence divergence was 1.91%. Nested clade analysis revealed allopatric fragmentation within O. irroratus. Chromosomal characters also support the two evolutionary lineages as clade A has pericentric inversions which occur as floating polymorphisms which are absent in clade B. Clade B in turn is fixed for a complex tandem fusion rearrangement which is absent from clade A. Divergence date estimates indicate that the two clades separated around 1.1 MYA, which coincides with climate changes since the late Pliocene/Pleistocene epochs. Cladogenesis within this species complex could therefore have been influenced by habitat fragmentation. A full taxonomic review of O. irroratus is therefore warranted by this study.AFRIKAANSE OPSOMMING: Die suider Afrikaanse vlei rot, Otomys irroratus word gekenmerk deur fenotipiese konservatisme regoor die spesie se verspreiding en het groot chromosomale variasie met diploied chromosoom getalle wat reeks vanaf 2n = 23 tot 2n = 32. Hierdie variasie binne O. irroratus het gelei tot die beskrywing van drie chromosomale groupe naamlik die A sitotipe wat gekenmerk word deur 'n akrosentriese komplement. Die tweede groep wat die B sitotipe genoem word besit ten minste agt chromosoom pare met heterokromatiese kort arms, onderwyl die derde group (die C sitotipe) vier chromosoom pare het met heterokromatiese kort arms. Hierdie studie bestudeer die bevolkings genetika struktuur van O. irroratus deur 102 monsters te analiseer wat gekollekteer was regoor die spesie se verspreiding binne Suid-Afrika en die mitochondriale merker sitokroom b sowel as chromosoom fluoressent hibridisasie te gebruik. Ek het 55 monsters van sewe lokaliteite binne Suid-Afrika sitogeneties geanaliseer deur gebruik te maak van G- en C-bandbepaling asook die hibridisasie patrone geproduseer deur die vloeisorteerde chromosoome van Myotomys unisulcatus. Die analise het gewys dat 47% van die monsters perisentromeriese inversies besit het, wat slegs aangetref was of die outosome OIR1, OIR4, OIR6 en OIR10. Hierdie inversies was nooit almal teenwoordig binne dieselfde monster nie en was gevind in beide heterosigotiese en homosigotiese vorm. Die inversies kom ook voor oor 'n wye verspreiding wat daarop aandui dat dit swerwende polymorfisme is. Omdat inversies lei tot die produksie van aneuploiede gamete speel hulle 'n belangrike rol in post-parings reproduktiewe isolasie, die verskyning van swerwende inversies binne vlei rotte dui dus daarop dat hulle onderhou word binne populasie verband deur die onderdrukking van rekombinasie in die gedeeltes van die chromosoom. Verdere verskille tussen populasies behels die voorkoms of afwesigheid van heterochromatiese kort arms wat (nie inversies) wat lei tot die variasies in die Nfa (40 – 49). Die variasie in diploied getal (2n = 28 – 32) is eksklusief as gevolg van B chromosoome. Ag-NOR banding het ook gewys dat daar twee evolusionêre lyne binne O. irroratus voorkom. Verder het filogenetiese analise van al die monsters verkryg deur volgorde-bepaling met behulp van maksimale parsimonie en Bayesian afleiding twee klades geidentifiseer. Klade A diere kom voor in die Wes en Oos-Kaap provinsies van Suid-Afrika terwyl klade B diere voorkom in die Oos-Kaap, Vrystaat, KwaZulu-Natal, Noord-Kaap en Mpumalanga provinsies onderskeidelik van Suid-Afrika. Die gemiddelde volgorde-bepalings verskille beloop 7% tussen die twee hoof klades (A en B) en tussen sub-klades 4.8%, terwyl binne klade A die verskille slegs 1.91% beloop het. Analise van die verwantskap tussen die klades het gewys dat allopatriese fragmentasie heel waarskynlik gelei het tot die populasie genetiese struktuur binne O. irroratus. Chromosoom karakters onderskraag die twee evolusionêre lyne waar klade A slegs perisentriese inversies besit wat swerwend wat ontbreek in klade B. Klade B op sy beurt besit 'n komplekse tandemme fusie wat glad nie voorkom in klade A nie. Molekulêre datering het verder gewys dat die twee klades omtrent 1.1 miljoen jaar gelede versprei het, wat ooreenstem met die klimaats veranderinge wat sedert die Peioceen en Pleistoceen plaasgevind het. Klade vorming binne die spesies komples kan daarom as gevolg van habitat fragmentasie plaasgevind het. Hierdie studie dus noodsaak 'n volle taksonomiese ondersoek van O. irroratus ten einde vas te stel hoeveel spesies binne die komplex voorkom

SNP discovery and selection in Cape buffalo for bTB association study, using an African buffalo genome reference

Thesis (MSc)--Stellenbosch University, 2021.ENGLISH ABSTRACT: The African buffalo (Syncerus caffer) is an important herd-based bovid in Africa, which is ubiquitous across almost the entire continent. These animals also act as a maintenance host for the ever-present threat that is bovine tuberculosis (bTB). The animal facilitates the spread and continued existence of the health problem that is bTB amongst wildlife and domestic cattle populations throughout Africa, causing problems in terms of conservation and economic loss. The disease is endemic to the southern part of Africa, especially South Africa, where two major national parks, The Kruger National Park (KNP) and Hluhluwe-iMfolozi Park (HiP), are host to it. There are also spill-over events of the disease from animals to humans, which is especially problematic in South Africa where tuberculosis (TB) in humans is already a major health concern. This study aimed to use 40 high-quality low-coverage African buffalo whole genome sequences in conjunction with a species-specific reference genome to create a panel of single nucleotide polymorphisms (SNPs) for use in further research in genetic association in buffalo bTB susceptibility. The sequences were from 40 Cape buffalo from 4 South African national parks, namely KNP, HiP and two bTB unexposed regions, the Mokala National Park (MNP) and Addo Elephant National Park (AENP). From this we produced a panel of 3698 high quality SNPs across 26 immune related genes in the African buffalo genome. One hundred and forty-three of these SNPs in three genes from the panel was used in a preliminary targeted association test with bTB exposure, which produced 10 SNPs associated with TB exposure. This may aid in future research and subsequent association studies.AFRIKAANSE OPSOMMING: Geen opsomming beskikbaarMaster

Inhibition of Akt Attenuates RPO-Induced Cardioprotection

Previous studies have shown that red palm oil (RPO) supplementation protected rat hearts against ischaemia-reperfusion injury. Evidence from these studies suggested that Akt may be partly responsible for the observed protection. The aim of the current study was therefore to prove or refute the involvement of Akt in the RPO-induced cardioprotection by administration of a specific Akt inhibitor (A6730). Male Wistar rats were randomly divided into 2 groups: a control group receiving standard rat chow and an experimental group receiving standard rat chow plus 2 mL RPO for six weeks. Hearts were excised and mounted on the Langendorff perfusion system. Functional recovery was documented. A different set of hearts were freeze-clamped to assess total and phosphorylation status of Akt. Another set of hearts were subjected to the same perfusion conditions with addition of A6730. Hearts from this protocol were freeze-clamped and assessed for total and phospho-Akt. RPO improved functional recovery which was associated with increased phosphorylation of Akt on Ser473 and Thr308 residues. Blockade of Akt phosphorylation caused poor functional recovery. For the first time, these results prove that Akt plays an important role in the RPO-induced cardioprotection

Derivation of the effective action of a dilute Fermi gas in the unitary limit of the BCS-BEC crossover

The effective action describing the gapless Nambu-Goldstone, or Anderson-Bogoliubov, mode of a zero-temperature dilute Fermi gas at unitarity is derived up to next-to-leading order in derivatives from the microscopic theory. Apart from a next-to-leading order term that is suppressed in the BCS limit, the effective action obtained in the strong-coupling unitary limit is proportional to that in the weak-coupling BCS limit.Comment: 13 pages, no figures; v2: discussion of one-dimensional system and references adde

A New Dawn

BRICS is a significant player in the international arena. Thus, it is important for South Africa as a member of BRICS to explore the implications of the external and internal influences of BRICS. This includes comprehensive understanding of the international and national involvement of BRICS in education provision and introducing discovered influences in South African educational planning. The size of BRICS as international player, in different areas and on different levels, necessitates the research of its functioning and in this case the role of BRICS regarding education provisioning. Therefore, this research and analysis of the contribution of BRICS in education provision are an important addition to the field of effective Education. Through the preliminary literature reviews, we noticed that current studies often are quantitative in nature and lack comparative qualitative exploration about education development in BRICS countries. For this reason, the book titled BRICS Education: A new dawn, will contribute to the flourishment of quality education in South Africa and all BRICS nations. The book will also aim to encourage researchers to join efforts with other researchers of the five member states in order to learn from each other and to address common challenges. To that end, this research will generate scientific knowledge meant to maximize the readers, understanding of the current realities of the education aims at the national (each member state) and collective (BRICS organization) level. The authors of the book are interested in comparing the educational aims across the BRICS countries and explore how successfully these aims are being implemented on-the-ground. Through the discovering of similarities and differences in the educational aims of the five member states and the educational objectives of the BRICS-organization the readers of the book will be able to identify best practices that will allow member states to fulfill the education aims of the BRICS organization at large

Comparative phylogeography of parasitic Laelaps mites contribute new insights into the specialist-generalist variation hypothesis (SGVH)

BACKGROUND: The specialist-generalist variation hypothesis (SGVH) in parasites suggests that, due to patchiness in habitat (host availability), specialist species will show more subdivided population structure when compared to generalist species. In addition, since specialist species are more prone to local stochastic extinction events with their hosts, they will show lower levels of intraspecific genetic diversity when compared to more generalist. RESULTS: To test the wider applicability of the SGVH we compared 337 cytochrome oxidase I mitochondrial DNA and 268 nuclear tropomyosin DNA sequenced fragments derived from two co-distributed Laelaps mite species and compared the data to 294 COI mtDNA sequences derived from the respective hosts Rhabdomys dilectus, R. bechuanae, Mastomys coucha and M. natalensis. In support of the SGVH, the generalist L. muricola was characterized by a high mtDNA haplotypic diversity of 0.97 (±0.00) and a low level of population differentiation (mtDNA Fst= 0.56, p < 0.05; nuDNA Fst = 0.33, P < 0.05) while the specialist L. giganteus was overall characterized by a lower haplotypic diversity of 0.77 (±0.03) and comparatively higher levels of population differentiation (mtDNA Fst = 0.87, P < 0.05; nuDNA Fst = 0.48, P < 0.05). When the two specialist L. giganteus lineages, which occur on two different Rhabdomys species, are respectively compared to the generalist parasite, L. muricola, the SGVH is not fully supported. One of the specialist L. giganteus species occurring on R. dilectus shows similar low levels of population differentiation (mtDNA Fst= 0.53, P < 0. 05; nuDNA Fst= 0.12, P < 0.05) than that found for the generalist L. muricola. This finding can be correlated to differences in host dispersal: R. bechuanae populations are characterized by a differentiated mtDNA Fst of 0.79 (P < 0.05) while R. dilectus populations are less structured with a mtDNA Fst= 0.18 (P < 0.05). CONCLUSION: These findings suggest that in ectoparasites, host specificity and the vagility of the host are both important drivers for parasite dispersal. It is proposed that the SGHV hypothesis should also incorporate reference to host dispersal since in our case only the specialist species who occur on less mobile hosts showed more subdivided population structure when compared to generalist species

Phylogeography of the rodent mites Laelaps giganteus and Laelaps muricola using mitochondrial and nuclear DNA markers: an evolutionary approach to host-parasite interactions

Thesis (PhD)--Stellenbosch University, 2016.ENGLISH ABSTRACT: Laelaps giganteus and Laelaps muricola (Mesostigmata; Laelapidae) are widespread and locally abundant mites on small mammals in southern Africa. The large host range and complex life history of these ectoparasites suggest possible intraspecific cryptic diversity in these taxa. The mechanisms responsible for speciation in response to codiversification in parasite-host systems are poorly understood. Similarly, how biogeography, parasite life history, and host vagility influence evolutionary codivergences is at present unknown in mite systems in southern Africa. A comparative phylogeography approach was followed to study the evolution and taxonomy of two mite species and their known host species. The main objectives of the study were to: (1) investigate the evolutionary history and taxonomic status of two southern African Mesotigmatid mites, L. giganteus and L. muricola, using a multidisciplinary approach including a combination of mitochondrial and nuclear DNA markers and selected morphological characters, (2) apply a comparative phylogenetic framework to L. giganteus which is only found on a single rodent genus, Rhabdomys, in an attempt to better understand codivergence between parasites and hosts, particularly at the phylogeographic level, and (3) determine whether L. muricola with a wide host range, yet similar life history, would show similar phylogeographic patterning to the host specialist L. giganteus across southern Africa. To assess the genetic and morphological diversity in L. giganteus and L. muricola, 228 rodents were collected from eight localities in southern Africa. This sample included nine previously recorded host species and on these, L. muricola was predominantly recorded from Mastomys natalensis and Micaelamys namaquensis while L. giganteus was found on Rhabdomys dilectus and Lemniscomys rosalia. Phylogenetic analyses of mtDNA cytochrome oxidase subunit I (COI) and nuclear ITS1 data strongly supported the recognition of L. giganteus and L. muricola as distinct species, a scenario partly supported by sequence data of the Tropomyosin intron. Strong support for evolutionarily distinct lineages within L. giganteus was found: L. giganteus lineage 1 was confined to R. dilectus and L. giganteus lineage 2 was confined to L. rosalia. These host-specific monophyletic lineages were separated by 9.84% mtDNA sequence divergence and 3.44% nuclear DNA sequence divergence. Since quantitative morphometric analyses were not congruent with these findings, these two lineages more than likely represent cryptic species. Further sampling across southern Africa indicated that L. giganteus occurs on four rodent species within the genus Rhabdomys. Cytochrome Oxidase I parsimony haplotype networks derived for 262 host and 278 parasite specimens showed marked phylogeographic congruence, which was in part confirmed by analyses of the Tropomyosin (TropoM) intron. Although distance-based cophylogenetic analyses in AXPARAFIT failed to support significant mtDNA codivergences (P ≥ 0.020), event-based analyses revealed significant cophylogeny between Rhabdomys and L. giganteus lineages using CORE-PA (P = 0.046) and JANE (P = 0.000). These findings, in conjunction with the weak congruence previously reported among the permanent ectoparasitic lice Polyplax and Rhabdomys, suggest that parasite-host intimacy (time spent on the host) is not the main driver of significant codivergence in the study system. Instead the restricted dispersal ability of L. giganteus resulted in strong spatial structuring and when this was coupled to an intimate relationship with the host, significant codivergence emerged. Both event-based reconstruction methods also indicated host switching that in some instances could be linked to climate-induced range shifts in the host distribution. When host range shifts occur, the phylogeographic signature of L. giganteus is preserved, as the genetic contribution of the dispersing individuals is overwhelmed by the large number of individuals already present in nests within the new environment, a phenomenon described as a parasite “drowning on arrival”. Novel phylogeographic insights into the host range of L. muricola are also shown, expanding the contemporary information available on this species in southern Africa. Results show the first evidence of a putative cryptic L. muricola lineage on the brown rat, Rattus norvegicus, present in South Africa. On native hosts, L. muricola indicate a lack of phylogeographic structuring owing to its generalist life style and the unique life history of some of its hosts. Mastomys coucha and M. natalensis are able to survive in multiple refugia and rapidly expand once favourable conditions set in. The pattern we find in this host generalist confirms that host dispersal is driving the genetic structure in both L. muricola and L. giganteus.AFRIKAANSE OPSOMMING: Die parasitiese myte, Laelaps giganteus en Laelaps muricola (Mesostigmata; Laelapidae) is wydverspreid en volop op klein soogdiere in suider Afrika. Die groot gasheer spektrum en komplekse lewensgeskiedenis van hierdie ektoparasiete mag aandui dat daar moontlike intraspesifieke kriptiese diversiteit in hierdie taxa is. Die meganismes verantwoordelik vir hierdie patrone en spesiasie met die klem op ko-diversifikasie in parasiet-gasheer stelsels is egter onduidelik op die oomblik. Hoe prosesse soos biogeografie, parasiet lewensgeskiedenis en gasheer verspreiding evolusionêre ko-diversifikasie beinvloed is ook tans heeltemal onbekend in myt biologiesie stelsels in Suid-Afrika. Hier word „n vergelykbare filogeografiese benadering tussen die twee mytspesies en hulle bekende gasheerspesies gevolg. Die hoof doelstellings van die studie was om: (1) die evolusionêre geskiedenis en taksonomiese status van twee suider-Afrikaanse Mesostigmata myte, L. giganteus en L. muricola, te ondersoek deur gebruik te maak van „n multi-dissiplinêre benadering wat „n kombinasie van mitokondriale DNS (mtDNS), kernDNS merkers en uitgesoekte morfologiese karakters insluit (2) „n vergelykbare filogenetise raamwerk tussen L. giganteus en Rhabdomys te gebruik in „n poging om meer duidelikheid te kry oor hoe parasiete met hul gashere op filogeografie vlak ko-diversifiseer, en (3) te bepaal of die ruimtelike genetiese struktuur van L. muricola, „n myt met „n weier gasheerspektrum, ooreenstem met die van L. giganteus, „n spesie met „n nouer gasheerspektrum, in suider Afrika. Om die genetiese en morfologiese diversiteit in L. giganteus en L. muricola te bepaal is 228 klein soögdiere van agt lokaliteite in Suid-Afrika versamel. Hier was nege van die voorheen geidentifiseerde gashere versamel. Laelaps muricola was waargeneem op Mastomys natalensis en Micaelamys namaquensis terwyl L. giganteus slegs op Rhabdomys dilectus en Lemniscomys rosalia gevind was. Filogenetise analises van die mtDNS (COI) en kernDNS (ITS1) data het oorweldigende ondersteuning aangedui dat L. giganteus en L. muricola as twee aparte spesies beskryf moet word terwyl die TropoM kernDNS interon dit deels ondersteun het. Sterk ondersteuning is ook verleen dat twee nuwe afstammelinge binne L. giganteus voorkom: L. giganteus lyn 1 kom slegs voor op R. dilectus terwyl die L. giganteus lyn 2 slegs op L. rosalia voorkom. Hierdie gasheer spesifieke monofiletiese lyne is ook geskei deur 9.84% mtDNS volgorde bepaling divergensie en 3.44% kernDNS volgorde bepaling divergensie. Siende dat kwantitatiewe morfometriese ontledings nie die genetiese onderskeiding ondersteun het nie verteenwoordig die twee heel waarskynlik kriptiese spesies. Verdere versameling van gashere om die patroon te bevestig het getoon dat L. giganteus op vier ander spesies binne die genus Rhabdomys voorkom. Sitochroom Oxidase I parsimoniese haplotiepe netwerke wat gebaseer is op 262 gasheer en 278 parasiet individue het aangedui op duidelike filogeografiese ooreenkomste, wat deels bevestig was deur analises van die TropoM intron. Alhoewel afstand-gebaseerde ko-filogenetiese ontledings in AXPARAFIT nie ko-diversifikasie ondersteun nie (P > 0.02), het gebeurtenis-gebaseerde ontledings getoon dat beduidende ko-filogenie tussen Rhabdomys en L. giganteus afstammelinge (CORE-PA: P = 0.046 and JANE: P = 0.00) bestaan. Hierdie bevindinge en die swak kongruensie wat voorheen vir die permanente ekto-parasitiese luis Polyplax op Rhabdomys genoteer was is teenstrydig met die voorspelling dat gasheer-parasiet intimiteit (tyd gespandeer op die gasheer) die hoof dryfkrag is van beduidende ko-diversifikasie. Hier stel die bevindinge ook voor dat die filogeografiese sein afgegee deur „n parasiet bevolking behou word na nuwe individue aansluit by die lokale bevolking. Hierdie verskynsel word beskryf as die parasiet “verdrink by aankoms”. Nuwe inligting oor die gasheerspektrum van L. muricola in suider Afrika is ook gevind. Bewyse word hier gelewer oor „n moonlike kriptiese parasiet wat op die indringer bruin rot, Rattus norvegicus, voorkom in Suid-Afrika. Verdere resultate dui daarop dat waneer na die natuurlike geshere van L. muricola gekyk word, geen filogeografiese stuktuur voorkom nie. Die patroon mag dalk veroorsaak word deur die feit dat L. muricola se gashere in verskeie habitatte kan oorleef en vinnig kan aanteel en versprei wanneer goeie toestande aanbreek.National Research Foundation (NRF

Phylogeography of the southern African vlei rat, Otomys irroratus, inferred from chromosomal and DNA sequence data

Thesis (MSc)--University of Stellenbosch, 2010.ENGLISH ABSTRACT: This study examines the phylogeography of the southern African vlei rat, Otomys irroratus using the mtDNA cyt b gene and chromosomal data derived using G-, and C-banding, Ag-NOR staining and fluorescence in situ hybridization (FISH using flow sorts of Myotomys unisulcatus). A total of N = 102 specimens were used from the Western Cape, Eastern Cape, Northern Cape, Free State, Mpumalanga and KwaZulu-Natal provinces of South Africa. Of the N = 102, N = 55 comprised fresh material while N = 47 comprises museum material obtained from the Durban Natural Science Museum of South Africa. Cytogentic analysis of N = 55 specimens collected from seven localities in South Africa revealed intra-specific variation resulting from two rearrangements, namely pericentric inversions and heterochromatin variation. Of the 55 specimens that were analyzed 47% contained inversions or centromeric shifts on four autosomes (OIR1, OIR4, OIR6 and OIR10) which were present singly in specimens (i.e. none of the specimens contained all four inversions concurrently). These inversions were present in both homozygous and heterozygous state over a wide geographic range suggesting that they are floating polymorphisms. Given the potential role of inversions in post-mating isolation (through production of aneuploid gametes), the prevalence of inversions as floating polymorphisms in the vlei rats suggest that they are probably retained in the population through suppression of recombination in the inverted regions of the chromosomes. In addition, differences between populations is due to the presence or absence of heterochromatic arms (and not inversions), which cause variation in the NFa (40 – 49) and supernumerary B chromosomes, resulting in the variation in diploid number (2n = 28 – 32). Analysis of N = 55 specimens revealed Ag-NORs on 7 autosomal pairs 1, 2, 5, 7, 8 and 9 proximal to the centromere on the short arm of the chromosome. Pair 8 also displayed Ag-NOR at the distal end of the long arm of the chromosome in individuals from the Free State province. Pair 3 showed two Ag- NORs occurring proximal to the centromere on the short arm and on the terminal end of the long arm, respectively. I obtained 953bp of mtDNA cyt b from fresh material and 400bp from museum material. Using maximum parsimony and Bayesian inference two main clades were retrieved. Clade A specimens occur mainly in the Western and Eastern Cape provinces of South Africa. Clade B specimens occur in the Eastern Cape, Free State, KwaZulu-Natal, Northern Cape and Mpumalanga provinces of South Africa. The mean sequence divergence between the main clades (A and B) is 7.0% and between sub-clades comprising clade B is 4.8%, while within clade A the sequence divergence was 1.91%. Nested clade analysis revealed allopatric fragmentation within O. irroratus. Chromosomal characters also support the two evolutionary lineages as clade A has pericentric inversions which occur as floating polymorphisms which are absent in clade B. Clade B in turn is fixed for a complex tandem fusion rearrangement which is absent from clade A. Divergence date estimates indicate that the two clades separated around 1.1 MYA, which coincides with climate changes since the late Pliocene/Pleistocene epochs. Cladogenesis within this species complex could therefore have been influenced by habitat fragmentation. A full taxonomic review of O. irroratus is therefore warranted by this study.AFRIKAANSE OPSOMMING: Die suider Afrikaanse vlei rot, Otomys irroratus word gekenmerk deur fenotipiese konservatisme regoor die spesie se verspreiding en het groot chromosomale variasie met diploied chromosoom getalle wat reeks vanaf 2n = 23 tot 2n = 32. Hierdie variasie binne O. irroratus het gelei tot die beskrywing van drie chromosomale groupe naamlik die A sitotipe wat gekenmerk word deur 'n akrosentriese komplement. Die tweede groep wat die B sitotipe genoem word besit ten minste agt chromosoom pare met heterokromatiese kort arms, onderwyl die derde group (die C sitotipe) vier chromosoom pare het met heterokromatiese kort arms. Hierdie studie bestudeer die bevolkings genetika struktuur van O. irroratus deur 102 monsters te analiseer wat gekollekteer was regoor die spesie se verspreiding binne Suid-Afrika en die mitochondriale merker sitokroom b sowel as chromosoom fluoressent hibridisasie te gebruik. Ek het 55 monsters van sewe lokaliteite binne Suid-Afrika sitogeneties geanaliseer deur gebruik te maak van G- en C-bandbepaling asook die hibridisasie patrone geproduseer deur die vloeisorteerde chromosoome van Myotomys unisulcatus. Die analise het gewys dat 47% van die monsters perisentromeriese inversies besit het, wat slegs aangetref was of die outosome OIR1, OIR4, OIR6 en OIR10. Hierdie inversies was nooit almal teenwoordig binne dieselfde monster nie en was gevind in beide heterosigotiese en homosigotiese vorm. Die inversies kom ook voor oor 'n wye verspreiding wat daarop aandui dat dit swerwende polymorfisme is. Omdat inversies lei tot die produksie van aneuploiede gamete speel hulle 'n belangrike rol in post-parings reproduktiewe isolasie, die verskyning van swerwende inversies binne vlei rotte dui dus daarop dat hulle onderhou word binne populasie verband deur die onderdrukking van rekombinasie in die gedeeltes van die chromosoom. Verdere verskille tussen populasies behels die voorkoms of afwesigheid van heterochromatiese kort arms wat (nie inversies) wat lei tot die variasies in die Nfa (40 – 49). Die variasie in diploied getal (2n = 28 – 32) is eksklusief as gevolg van B chromosoome. Ag-NOR banding het ook gewys dat daar twee evolusionêre lyne binne O. irroratus voorkom. Verder het filogenetiese analise van al die monsters verkryg deur volgorde-bepaling met behulp van maksimale parsimonie en Bayesian afleiding twee klades geidentifiseer. Klade A diere kom voor in die Wes en Oos-Kaap provinsies van Suid-Afrika terwyl klade B diere voorkom in die Oos-Kaap, Vrystaat, KwaZulu-Natal, Noord-Kaap en Mpumalanga provinsies onderskeidelik van Suid-Afrika. Die gemiddelde volgorde-bepalings verskille beloop 7% tussen die twee hoof klades (A en B) en tussen sub-klades 4.8%, terwyl binne klade A die verskille slegs 1.91% beloop het. Analise van die verwantskap tussen die klades het gewys dat allopatriese fragmentasie heel waarskynlik gelei het tot die populasie genetiese struktuur binne O. irroratus. Chromosoom karakters onderskraag die twee evolusionêre lyne waar klade A slegs perisentriese inversies besit wat swerwend wat ontbreek in klade B. Klade B op sy beurt besit 'n komplekse tandemme fusie wat glad nie voorkom in klade A nie. Molekulêre datering het verder gewys dat die twee klades omtrent 1.1 miljoen jaar gelede versprei het, wat ooreenstem met die klimaats veranderinge wat sedert die Peioceen en Pleistoceen plaasgevind het. Klade vorming binne die spesies komples kan daarom as gevolg van habitat fragmentasie plaasgevind het. Hierdie studie dus noodsaak 'n volle taksonomiese ondersoek van O. irroratus ten einde vas te stel hoeveel spesies binne die komplex voorkom

Going it alone? : an evaluation of American concerns about the international criminal court

Thesis (MA)--University of Stellenbosch, 2002.ENGLISH ABSTRACT: The International Criminal Court (ICC) is an exciting new development in the international system. It is not without its detractors, however, amongst others the United States. The fact that the United States takes a strong stance against the ICC creates uncertainty in the international system. This uncertainty is linked to the role of the United States as the only remaining superpower in this system. The main concern of the United States about the ICC is that an American might be brought before the court in terms of politically motivated charges. To illustrate this concern, the United States offers five basic arguments. These five are condensed into three arguments that form the main body of this thesis. They are the questions related to the jurisdiction of the ICC, the role of the United Nations Security Council in the functioning of the ICC, and the influence that the United States constitution might have on the ICC. Close attention is also paid to the political implications of the stance taken by the United States, both in terms of the specific arguments, and in general. The different arguments are tested against certain criteria, which include the stipulations of the ICC Statute and other counter arguments. From these comparisons, certain evaluations can be made, from which conclusions are drawn. For various reasons, none of the arguments put forward have merit when tested against the stipulations of the ICC Statute. What this implies is that the United States does not have real evidence to back its main concern about the ICC. Even though the possibility exists that an American could be charged before the court, there are sufficient safeguards to protect such a person from actually appearing before the court. The very real political implication then becomes that the United States is undermining its position and relative power in the international system by taking such a unilateral stAFRIKAANSE OPSOMMING: Die Internasionale Kriminele Hof (IKH) is 'n opwindende ontwikkeling in die internasionale sisteem. Dit is egter nie sonder opponente nie, wat onder andere die Verenigte State van Amerika insluit. Die feit dat Amerika so sterk standpunt teen die hof inneem, skep onsekerheid in die internasionale sisteem. Die onsekerheid hou verband met Amerika se rol as die enigste oorblywende supermoontheid binne die sisteem. Amerika se hoof besorgdheid met die IKH is dat 'n Amerikaner dalk in terme van polities-gemotiveerde aanklagte voor die hof gedaag sal word. Hierdie besorgdheid word geïllustreer deur vyf basiese argumente wat geopper word. Hierdie argumente word in drie spesifieke argumente wat die basis van die tesis vorm, gefokus. Die argumente is die vrae in terms van die jurisdiksie van die IKH, die rol van die Veiligheidsraad van die Verenigde Nasies in die funksionering van die IKH, en die invloed wat die Amerikaanse grondwet op die IKH het. Daar word ook gekyk na die politieke implikasies van die Amerikaanse standpunt, beide in terme van die spesifieke argumente en in die algemeen. Die verskillende argumente word teen sekere kriteria getoets, wat die stipulasies van die IKH Statuut en ander teenargumente behels. Vanaf hierdie vergelykings kan evaluerings gedoen word, waarvan daar gevolgtrekkings gemaak word. Vir verskeie redes het nie een van die spesifieke argumente meriete as dit teen die bepalings van die IKH Statuut getoets word nie. Dit impliseer dat Amerika nie werklik bewyse vir hul hoof besorgdheid met betrekking tot die IKH het nie. Selfs al is die moontlikheid daar dat 'n Amerikaner wel voor die hof gedaag kan word, is daar voldoende waarborge om so persoon teen 'n verskyning voor die hof te beskerm. Die werklike politieke implikasie is nou dat Amerika sy posisie en relatiewe mag in die internasionale sisteem met sy eensydige standpunt teen die IKH ondermyn. Hierdie punt kan ook verdere uitgebreide implikasies hê

No evidence for host plant associated genetic divergence in a population of Bullacris unicolor (Linnaeus, 1758) (Orthoptera: Pneumoridae)

Host-associated genetic differentiation in grasshoppers has received limited attention, due to a lack of information on grasshopper-plant associations. The bladder grasshopper, Bullacris unicolor (Linnaeus, 1758) (Orthoptera: Pneumoridae), is a phytophagous species that can occur on at least six host plants within its geographic range. However, the relationship between host plant association and genetic variation of bladder grasshoppers has not been studied before. In light of this, the present study examined host plant-related genetic [mitochondrial cytochrome oxidase 1 (CO1) and the internal transcribed spacer (ITS) gene regions] and morphological (antennal length, body length, head width, abdomen width, femur length, tibia length and pronotum length) divergence within a population of B. unicolor. We used two plant species, belonging to different families, namely Didelta spinosa (L.fil.) Aiton (Asteraceae) and Roepera morgsana (L.) Beier &amp; Thulin (Zygophyllaceae), to evaluate variation between individuals collected on these two sympatric host plants at a single locality in the Northern Cape, South Africa. The results demonstrated non-significant host related genetic variation with very low values of FST, indicating a low level of variation. The phylogram strongly indicated that there are no host-associated genetic differences in B. unicolor by displaying limited genomic clustering, whereas some differentiation was observed between the morphological measurements of males and females among host plants. Further studies using microsatellite molecular markers may help to discern population genetic structure. In addition, significant host-associated morphological divergence highlights the need to examine the mechanisms by which host utilization affects morphological features