Thesis (Ph.D.) -- University of Adelaide, Dept. of Animal Physiology, 1975.

Thesis (Ph.D.) - University of Queensland, 2006. / Includes bibliography.

Marsupials have complex and interesting socioecology and life history strategies that differ quite markedly to much - studied eutherian mammals. However, the socioecology and life history strategies of a number of Australian marsupials are most often observed only within the context of a much larger study on their ecology. My aim was to study, using a combination of behavioural observations and molecular DNA techniques, aspects of the socioecology of a population of yellow - bellied gliders ( Petaurus australis ) in Rennick State Forest, south - western Victoria. Petaurid gliders feed on plant and insect exudates, pollen / nectar and arthropods. Yellow - bellied gliders are arboreal, rare, nocturnal and cryptic, have persistent pair bonds, are territorial and exist in low population densities. In particular, I sought to confirm that the Rennick population of yellow - bellied gliders maintained a predominantly monogamous mating system. I also sought to confirm that the timing of reproduction in this population of yellow - bellied gliders would be seasonal, and timed to coincide with peaks in the abundances of two indices of protein food resources ( i.e. flowering and bark shed ). In a more broadscale study, I sought to examine the geographic distribution of mitochondrial haplotyes and morphological variation of the yellowbellied glider throughout its range. Polymorphic microsatellite loci are the choice of genetic marker for fine - scale studies, such as relatedness and paternity. Microsatellite loci had previously only been characterised and optimised for Petaurus norfolcensis ( squirrel gliders ). However, close inspection of the GenBank sequences revealed the presence of replicates differing only by sequencing errors. A panel of seven polymorphic tetranucleotide loci in Petaurus breviceps ( sugar gliders ) and three polymorphic trinucleotide loci in P. australis were isolated and optimised. Five P. breviceps loci were polymorphic in P. norfolcensis and two were polymorphic in P. australis. Only one P. australis locus was variable in P. breviceps and P. norfolcensis. No locus showed a deficit in heterozygotes according to Hardy - Weinberg expectations, and the large number of alleles for some of the loci confirmed their usefulness for studies in relatedness and paternity. A number of Australian arboreal marsupials have been reported to show monogamous and polygynous mating systems in different populations, but previous studies have not included genetic analyses to confirm the observations. My aim was to test the hypothesis that monogamy was the predominant mating system in a population of yellow - bellied gliders ( Petaurus australis ) in south - western Victoria. Home range overlap, cohesiveness of pairs, rates of den site co - occupancy and location of den trees within the home ranges of 13 gliders were determined via radio - tracking. A monogamous social system predominated, demonstrated by extensive home range overlap between cohabiting adult males and females ( 40 - 100 % ) and little home range overlap between adjacent territories ( < 7 % ). Males spent approximately 55 % of their active time within 25m of their female partners and 55 - 85 % of their sleeping time in dens with their female partner. The paternity of all juveniles within the population was analysed using five microsatellite DNA markers. Of 37 individuals genotyped, 12 of 13 juveniles could be attributed to the resident adult male. My results suggest that social monogamy equates with genetic monogamy in this population of yellow - bellied gliders. Mammalian taxa living in seasonal environments usually coincide energy - demanding reproductive activities with the seasonal availability of food resources. However, few studies on arboreal marsupial taxa in Australia have focussed upon the interplay of forest phenology and the timing of breeding. This study examined forest phenology in a temperate environment, and the timing of reproduction the yellow - bellied glider. I captured adult females once per month between August 2001 and August 2003 to determine reproductive condition, and monitored indicators for two key food resources over the same period. Flowering phenology ( as an index of pollen availability ) was assessed in 170 manna gum ( Eucalyptus viminalis ) and brown stringybark ( E. baxteri ) trees, while bark shed ( as an index of arthropod availability ) was assessed in 45 manna gum, the only eucalypt species at this site that sheds it bark. Aseasonal reproduction was indicated within this population of gliders, as distributions of births were not statistically different from random. However, yellow - bellied gliders did exhibit distinct birth peaks in spring, summer and winter, when data were combined for both years. The temporal distributions of flowering for both eucalypt species were statistically different from random, indicating seasonal availability of nectar and pollen. Peak flowering occurred in summer for brown stringybark, and autumn for manna gum in both years, although for manna gum peak abundance of flowers was one month earlier in the second year. While the temporal distribution of bark shed on the trunks of trees did not differ from random, it did show seasonality on the main and outer branches, peaking in summer and declining thereafter. Thus, it appears that yellow - bellied gliders breed aseasonally in a predictable, seasonal environment. However, yellow - bellied gliders have a reliance on the complex temporal interplay of different seasonal food resources. Subspecific status has often been used as a surrogate for conservation unit, but does not always reflect intra - specific lineages with different evolutionary histories. One contentious case of subspecific classification occurs in the yellow - bellied glider, a marsupial species showing considerable decline in population size and requiring conservation management. Our aim was to assess the current subspecific status of populations and define units of conservation using a combination of phylogeographical analyses of mitochondrial DNA and morphological analyses. Analyses of the mitochondrial ND4 gene provided evidence for significant phylogeographic structure within yellow - bellied gliders. Isolated populations in north Queensland ( NQ ) and Victoria / South Australia were genetically distinct from populations in New South Wales and southern Queensland. Morphological analyses provided little evidence for discrimination of populations, although NQ specimens were generally smaller in size compared to southern forms. My analyses do not support the classification of subspecies, P. a. reginae, for the original type specimen from southern Queensland. Taking into account other behavioural and ecological data, and the disjunct distribution of NQ populations from southern populations, I propose that the NQ population represents a distinct Evolutionarily Significant Unit, a lineage showing highly restricted gene flow with the rest of the species. / http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1281000 / Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2006.

No description available.

<p>Genomic imprinting is the parent-of-origin dependent monoallelic expression of select developmentally important genes that are regulated by epigenetic mechanisms. It is believed to have co-evolved with placentation in the Therian lineage, but it is unclear whether this phenomenon arose in a convergent or divergent manner in the Metatherians (those with a rudimentary placenta) and Eutherians (true placental mammals). Moreover, the precise epigenetic mechanisms involved in establishing genomic imprinting (DNA methylation or histone modifications) are still poorly defined. Thus, I studied Metatherian orthologues of Eutherian imprinted loci using Monodelphis domestica as a model organism. L3MBTL and HTR2A were monoallelically expressed; PEG1/MEST had one imprinted and one non-imprinted transcript, while IMPACT, COPG2 and PLAGL1 were not imprinted, thus revealing that this phenomenon is conserved at some, but not all loci between the two groups of Therians. Moreover, differential methylation patterns and the associated regulatory non-coding RNA are also not conserved amongst them, exemplified by the novel DMR identified within IGF2R which had no associated anti-sense transcript. However, histone modifications, specifically the activating H3 Lysine 4 dimethylation mark at the active allele's promoter seems to be important in both lineages and probably serves as the primordial imprint mark. Although the evidence does not resolve the issue of convergence or divergence, it raises the intriguing possibility that both forms of evolution occurred during establishment of imprinting in these mammals.</p> <p>The imposition of functional haploidy in the genome by such epigenetic mechanisms necessarily makes imprinted genes more susceptible to deleterious mutations and regulatory perturbations. Thus, imprinting is implicated in a number of developmental disorders, but its role in the etiology of complex human diseases and neurological disorders, like autism and schizophrenia, remains to be determined. I chose to investigate the imprint status of the duplicated locus DGCR6/DGCR6L lying within the 22q11.2 microdeletion causative of DiGeorge Syndrome (DGS), because our lab previously predicted genes at this genomic location to be imprinted. My studies revealed that both genes DGCR6 and DGCR6L are monoallelically expressed in the primate lineage, but not in a parent-of-origin dependent manner. Interestingly, DGCR6L is not present in the mouse, and Dgcr6 is expressed from both parental alleles.</p> <p>Although DGS primarily manifests as facial, limb and heart abnormalities in children, a number of these patients also ultimately present with variable neurocognitive defects. Thus, I focused my studies on determining the effect of the microdeletion at this chromosomal region on DGCR6 and DGCR6L expression because of their potential role in neural crest cell migration. This revealed that DGS subjects have a highly dysregulated pattern of DGCR6 and DGCR6L expression as compared to that in controls. Moreover, increased expression of these genes correlated significantly with decreased performance in sustained-attention tests. This provides the first evidence that disruption of the normal monoallelic expression pattern of DGCR6 and DGCR6L by hemizygous deletion is involved in the variability in neurocognitive symptoms associated with DiGeorge Syndrome. The results of my studies highlight the importance of searching for novel imprinted domains to better understand not only their evolution, but also the potential role of such epigenetically labile regions in modulating complex human diseases and neurological disorders.</p> / Dissertation

Thesis (Ph. D.)--University of Chicago, Committee on Evolutionary Biology, August 2003. / Includes bibliographical references. Also available on the Internet.

Thesis (PH.D.)--Columbia University, 1929. / Bibliography: p. 231-232.

Thesis (M.Sc. (Res.))--University of Wollongong, 2009. / Typescript. Includes bibliographical references: leaf 147-159.

One of the most diverse groups of parasitic nematodes includes the nematodes of the suborder Trichostrongylina. Trichostrongyle systematic classification is based on the study of the anterior end, the female reproductive system, the male copulatory bursa and cuticular ridges, which make up the synlophe. These morphological characters also assist taxonomists to characterize species and assign them into one of the three superfamilies. Heligmosomoidea is the most diverse superfamily, including Viannaiidae. This family represents one of the major evolutionary radiations of trichostrongyles in South America. Members of Viannaiidae parasitize a variety of mammals endemic to the Neotropics including, but not limited to, the opossums. Viannaiids have great morphological variation in the reproductive organs of the females and the secondary sexual structures of the males (e.g., rays in the bursa). Consequently, the placement of these species in classification schemes has drastically changed over time. The prevailing taxonomy relies on the host used by the parasites as well as their geographic distribution. Viannaiidae has always included monodelphic nematodes with simple synlophes, yet it eventually included species in the genus Travassostrongylus, which the morphology is very distinct from the rest of the members of the family. Differences pertain to a greater number of ridges of the synlophe and the didelphic female reproductive system. These features are more similar to trichostrongyles in Herpetostrongylidae and Nicollinidae, which infect Australian vertebrates, the majority of which are marsupials. I herein document the diversity of this group by reporting the presence of a putative new species and use five gene regions to reconstruct the phylogeny of Viannaiidae exclusive of didelphid marsupials. I used the resulting phylogeny to test the monophyly of Travassostrongylus and Viannaia and to reconstruct the character evolution of the monodelphic/didelphic condition and the ornamentation of the cuticle. The phylogeny indicates that Viannaiidae is not monophyletic, recovering a clade with the Travassostrongylus species and trichostrongyles from Australian fauna. The tests for character reconstruction assist in determining that the didelphic condition and the presence of dorsal synlophe ridges in Travassostrongylus and Austrostrongylus may be traits inherited from a common ancestor. Furthermore, it was apparent that a character change from didelphic to monodelphic occurred in the common ancestor of the Viannaia species. This ancestor also underwent a change from a dorsal cuticle with ridges to a smooth cuticle. Though the study suggests that Viannaiidae is not monophyletic, the inclusion of more species from these genera and the viannaiids found in hystricognaths from the New World rodents will conclusively determine the affinities of the members of the family. Finally, I suggest that the relationship between the species in Travassostrongylus and the Australian parasites dates to the Gondwana landmass and that these trichostrongyles, or their ancestors, were present in the marsupials of that time period. The examination of microbiotheriids could provide more information and illuminate the factors that led to the evolutionary relationship between the parasites of America and Australia.

Two species of Acantopcephala of the genus <i>gigantorhynchus</i> (<i>G. echinodiscus, G. Lutzi</i>) are considered with relation to the proposed new species, <i>Gigantorhynchus orticei</i>, found in the intestine of <i>Metachirus nudicaudatus</i> from Peru, South America. The specific name is dedicated to the late Javier Ortiz de la Puente, chief ornithologist of the Museum of San Marcos University, Lima, Peru. / Master of Science