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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Genetic linkage maps and population genetics of macropods

Zenger, Kyall Richard January 2002 (has links)
"November 2001". / Thesis (PhD)--Macquarie University, Division of Environmental and Life Sciences, Department of Biological Sciences, 2002. / Bibliography: leaves 136-157. / General introduction -- Molecular markers for comparative and quantitative studies in macropods -- Genetic linkage map construction in the tammar wallaby (M. eugenii) -- Intraspecific variation, sex-biased dispersal and phylogeography of the eastern grey kangaroo (M. giganteus) -- General discussion. / The analysis of DNA using molecular techniques is an important tool for studies of evolutionary relationships, population genetics and genome organisation. The use of molecular markers within marsupials is primarily limited by their availability and success of amplification. Within this study, 77 macropodid type II microsatellite loci and two type I genetic markers were characterised within M. eugenii to evaluate polymorphic levels and cross-species amplification artifacts. Results indicated that 65 microsatellite loci amplified a single locus in M. eugenii with 44 exhibiting high levels of variability. The success of crossspecies amplification of microsatellite loci was inversely proportional to the evolutionary distance between the macropod species. It is revealed that the majority of species within the Macropodidae are capable of using many of the available heterologous microsatellites. When comparing the degree of variability between source-species and M. eugenii, most were significantly higher within source species (P < 0.05). These differences were most likely caused by ascertainment bias in microsatellite selection for both length and purity. -- The production of a marsupial genetic linkage map is perhaps one of the most important objectives in marsupial research. This study used a total of 353 informative meioses and 64 genetic markers to construct a framework genetic linkage map for M. eugenii. Nearly all markers (93.7%) formed a significant linkage (LOD > 3.0) with at least one other marker. More than 70% (828 cM) of the genome had been mapped when compared with chiasmata data. Nine linkage groups were identified, with all but one (LG7; X-linked) allocated to the autosomes. Theses groups ranged in size from 15.7 cM to 176.5 cM, and have an average distance of 16.2 cM between adjacent markers. Of the autosomal linkage groups, LG2 and LG3 were assigned to chromosome 1 and LG4 localised to chromosome 3 based on physical localisation of genes. Significant sex-specific distortions towards reduced female recombination rates were revealed in 22% of comparisons. Positive interference was observed within all the linkage groups analysed. When comparing the X-chromosome data to closely related species it is apparent that it is conserved both in synteny and gene order. -- The investigation of population dynamics of eastern grey kangaroos has been limited to a few ecological studies. The present investigation provides analysis of mtDNA and microsatellite data to infer both historical and contemporary patterns of population structuring and dispersal. The average level of genetic variation across sample locations was exceedingly high (h = 0.95, HE = 0.82), and is one of the highest observed for marsupials. Contrary to ecological studies, both genic and genotypic analyses reveal weak genetic structure of populations where high levels of dispersal may be inferred up to 230 km. The movement of individuals was predominantly male-biased (average N,m = 22.61, average N p = 2.73). However, neither sex showed significant isolation by distance. On a continental scale, there was strong genetic differentiation and phylogeographic distinction between southern (TAS, VIC and NSW) and northern (QLD) Australian populations, indicating a current and / or historical restriction of geneflow. In addition, it is evident that northern populations are historically more recent, and were derived from a small number of southern eastern grey kangaroo founders. Phylogenetic comparisons between M. g. giganteus and M. g. tasmaniensis, indicated that the current taxonomic status of these subspecies should be revised as there was a lack of genetic differentiation between the populations sampled. / Mode of access: World Wide Web. / xv, 182 leaves ill
22

The detection and characterisation of Helicobacter species in Australian marsupials

Coldham, Thosaporn. January 2004 (has links)
Thesis (Ph. D.)--University of New South Wales, 2004. / Title from PDF title page (viewed on Mar. 25, 2006). Includes bibliographical references (p. 264-286).
23

Contribuição ao estudo da distribuição geográfica e biologia do gênero Didelphis (Mammalia, Marsupialia) no estado de Minas Gerais, Brasil

Varejão, José Benedito Malta January 1981 (has links)
Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2017-09-15T23:58:16Z No. of bitstreams: 1 200795.pdf: 11906807 bytes, checksum: 4431620b426de68cc14cac3e642f6f7d (MD5) / Made available in DSpace on 2017-09-15T23:58:16Z (GMT). No. of bitstreams: 1 200795.pdf: 11906807 bytes, checksum: 4431620b426de68cc14cac3e642f6f7d (MD5) Previous issue date: 1981 / CAPES / Indisponível.
24

Comportamento postural e locomotor ao escalar de sete espécies marsupiais (Didelphimorphia) da Mata Atlântica

Antunes, Vanina Zini 10 1900 (has links)
Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2017-10-18T21:15:39Z No. of bitstreams: 1 840750.pdf: 6317284 bytes, checksum: b94fea19591f90b9cce6e2a4c020af8a (MD5) / Made available in DSpace on 2017-10-18T21:15:39Z (GMT). No. of bitstreams: 1 840750.pdf: 6317284 bytes, checksum: b94fea19591f90b9cce6e2a4c020af8a (MD5) Previous issue date: 2003-10 / CAPES / FUJB / A utilização diversificada do estrato arbóreo pelos didelfídeos é decorrente do tamanho do corpo e de características anatômicas ou da partilha dos recursos. Essa diversificação da habilidade arborícola é pouco conhecida e seu estudo pode revelar comportamentos específicos. Neste trabalho analisou-se e comparou-se o modo de escalar suportes verticais de setes espécies: Caluromys philander (arborícola de dossel), Gracilinanus microtarsus, Micoureus travassossi, Marmosops incanus (arborícolas de sub-bosque), Didelphis aurita, Philander frenatus (semi-terrestres) e Metachirus nudicaudatus (terrestre). Esperava-se encontrar diferenças nas estratégias de locomoção relacionadas ao estrato vertical utilizado e à velocidade atingida. Os animais foram capturados em áreas de Mata Atlântica, RJ, e removidos. Em laboratório, realizaram-se testes locomotores em cordas de nylon, dispostas verticalmente, com três diâmetros. Os testes foram gravados em vídeo e as imagens digitalizadas para análise do modo de escalar. Com diagramas de locomoção e análise quadro a quadro da imagem, selecionou-se o animal mais veloz e com postura típica da espécie. Para a comparação entre diferentes velocidades, selecionou-se um ciclo de passada de dois indivíduos (um com velocidade mínima, e outro, máxima) de cada espécie, nos três suportes. Classificou-se a passada com gráfico de locomoção. Os arborícolas apresentaram movimentação dos membros característica de trote, diferente das demais espécies e mantiveram-se afastados da corda. M. incanus e P. frenatus alteraram a passada ao diminuir a velocidade, e passaram de dois para três apoios. A cauda não foi utilizada na escalada. Portanto, pode-se concluir que os arborícolas têm maior estabilidade e desenvoltura ao escalar, por conseguirem atingir alta velocidade com dois apoios e manterem-se afastados do suporte. / The stratification of didelphids on the arboreal strata seem to be related to their body size, anatomical differences and resources partitioning. Researches on their arboreal ability are still lacking and they could reveal specifics behaviors. ln this study was investigated climbing gait on vertical supports of seven species: Caluromys philander (canopy arboreal), Gracilinanus microtarsus, Micoureus travassossi, Marmosops incanus (understory arboreal), Didelphis aurita, Philander frenatus (semi-terrestrials) e Metachirus nudicaudatus (terrestrial). It was expected distinct locomotion strategies related to the arboreal stratum utilized and to the reached speed. The animais were trapped in Atlantic forest areas, RJ, and removed. At the laboratory, locomotory tests were applied with vertically nylon ropes with three diameters. These tests were filmed and the images digitized for climbing analysis. Gait diagrams and a frame-by-frame analysis were made to select the individual with the fast gait sequence and a typical climbing posture of its species. To compare differences according to speeds, a gait sequence from two individuais were selected (one in the minimum other in the maximum speed) of each species, on the three ropes. Locomotion graph was used to classify the gait sequences. The arboreal species moved their limbs like a trot, been different from the other species and maintained their body far off the rope. M. incanus and P. frenatus altered their gait sequences with the speed reduction, and relied on three limbs. The tail was not useful for climbing. Thus, arboreal species had more stability and agility climbing, for been able to reach high speed with two support limbs and maintain their body far off the rope.
25

Reproductive strategies of K/t-crossing Theria

Szdzuy, Kirsten 07 June 2006 (has links)
Die Dissertation beschäftigt sich mit den möglichen Gründen für die divergente evolutionäre Entwicklung von Beuteltieren und plazentalen Säugetieren nach der Kreide/Tertiär-Grenze. Eine Erklärung könnten ihre unterschiedlichen Reproduktionsstrategien sein. Während die Beuteltiere sehr embryonale Jungtiere nach einer kurzen Tragzeit gebären, bringen Plazentalier deutlich weiter entwickelte Jungtiere nach einer relativ langen Tragzeit zur Welt. Die Aufrechterhaltung eines stabilen Metabolismus und thermoregulatorische Fähigkeiten der Jungtiere bieten einen großen Vorteil für die Anpassungsfähigkeit an ungünstige Umweltbedingungen, wie sie für die K/T-Grenze vermutet werden. Aus diesem Grund untersucht diese Studie den strukturelle Entwicklungsgrad der Lunge und die metabolischen Fähigkeiten von neonaten Marsupialia und Plazentalia. Histologische, ultrastrukturelle und kalorimetrische Untersuchungen erfolgten in einer integrativen Studie. Basierend auf den Ergebnissen wurde eine Grundplanrekonstruktionen der Neonaten von Marsupialia und Plazentalia durchgeführt. Als Vertreter für nesthockende Plazentalia wurde der Goldhamster (Mesocricetus auratus), die Moschusspitzmaus (Suncus murinus) und das Belangeri Spitzhörnchen (Tupaia belangeri) untersucht. Das Wildmeerschweinchen (Cavia aperea) und die Kurzohr-Elefantenspitzmaus (Macroscelides proboscideus) repräsentieren die nestflüchtenden Plazentalia. Als Marsupialia wurden die Hausspitzmaus-Beutelratte (Monodelphis domestica) und das Tammar-Wallaby (Macropus eugenii) untersucht. Die Ergebnisse bestätigen die starken Unterschiede im Entwicklungsgrad der Neonaten und in der postnatalen Entwicklung zwischen Marsupialia und Plazentalia. Die neonatalen Lungen von M. auratus und S. murinus befinden sich im späten “terminal air sac”-Stadium und weisen viele kleine Atemkammern von 50-80 µm Durchmesser auf. Die Alveolenbildung erfolgt bei M. auratus und S. murinus bereits im Alter von zwei beziehungsweise vier Tagen. Bei T. belangeri, C. aperea und M. proboscideus sind Alveolen bereits zum Zeitpunkt der Geburt vorhanden. Im Gegensatz dazu, befinden sich die Lungen der neonaten Beuteltiere M. domestica und M. eugenii im frühen “terminal air sac”-Stadium mit wenigen großen Atemkammern von 300-400 µm im Durchmesser. Die postnatale Lungenentwicklung erfolgt sehr langsam und die Alveolenbildung startet mit 28 Tagen bei M. domestica und mit 65 Tagen bei M. eugenii. Die Metabolismusmessungen ergaben, daß Marsupialia mit einer niedrigen Metabolismusrate geboren werden und den Adultmetabolismus erst spät in der postnatalen Entwicklung erreichen. Einhergehend mit der weit entwickelten Lungenstruktur weisen die Plazentalia hohe Metabolismusraten zur Geburt auf und erreichen den Adultmetabolismus innerhalb der ersten Lebenswoche. Die Ergebnisse zeigen, dass Jungtiere der Plazentalia, im Vergleich zu jungen Marsupialia, eine höhere Widerstandskraft gegen Umweltschwankungen haben, was als ein evolutiver Vorteil der Reproduktionsstrategie der Plazentalia unter ungünstigen Klimabedingungen interpretiert werden kann. / This project deals with the possible reasons for the evolutionary differentiation between marsupial and placental mammals after the K/T-event. One explanation could be their different reproductive patterns. Marsupialia bear virtually embryonic young after a brief gestation period. In contrast, many eutherians bear anatomically advanced, highly precocious young after a relatively long gestation period. A stable metabolism and thermoregulatory abilities of the young are considered to offer a large adaptive advantage in a changing environment, how it is presumed for the K/T-boundary. Therefore this study determines the developmental stage and the respiratory efficiency of the lungs of marsupial and placental young. Histological, ultrastructural and calorimetric investigations were carried out in an integrated study and from the results morphotype reconstructions of the marsupial and placental neonates were carried out. As representatives for altricial Placentalia, the Golden hamster (Mesocricetus auratus), the Musk shrew (Suncus murinus), and the Belanger’s tree shrew (Tupaia belangeri) were examined. Furthermore the Guinea pig (Cavia aperea) and Short-eared elephant shrew (Macroscelides proboscideus) as typical precocial Placentalia were included. The Marsupialia were represented by the Grey short-tailed opossum (Monodelphis domestica) and the Tammar wallaby (Macropus eugenii). The results confirm clear differences in the developmental degree of the neonates and the postnatal development between marsupial and placental mammals. The newborn lungs of the altricially born placentals M. auratus and S. murinus are at the late terminal air sac stage with numerous small air sacs of 50 - 80 µm in diameter. Alveoli are formed shortly after birth at the age of 2 days in M. auratus and at the age of 4 days in S. murinus. In T. belangeri and in the precocially born C. aperea alveoli are already present at birth. In contrast, the lungs of the newborn marsupials M. domestica and M. eugenii are at the early terminal air sac stage with few large air sacs of 300 – 400 µm in diameter. The postnatal lung development proceeds very slowly in marsupials and alveoli are not present before the age of 28 days in M. domestica and 65 days in M. eugenii. The metabolic investigations demonstrate that Marsupialia have a low metabolism at birth and achieve the adult metabolism late in the postnatal development. All examined Placentalia showed the same pattern of oxygen consumption. Corresponding to their advanced differentiation of the lungs they also exhibit high metabolic abilities at birth and reach the adult metabolism during the first week of life. During this critical period placental young have a higher resistance against certain environmental stresses than marsupial young and this could mean an evolutionary advantage of the placental “reproductive strategy” under suboptimal climatic conditions.
26

Avaliação da diversidade e estrutura genética de Micoureus paraguayanus (Didelphidae) através do marcador mitocondrial d-loop no Parque Estadual Morro do Diabo e em fragmentos de Mata Atlântica adjacentes

Cattony Neto, Pedro de Queiroz 25 June 2009 (has links)
Made available in DSpace on 2016-06-02T20:21:23Z (GMT). No. of bitstreams: 1 2705.pdf: 4158508 bytes, checksum: e7be7fc76294b9361bf22b40ad1ada06 (MD5) Previous issue date: 2009-06-25 / Financiadora de Estudos e Projetos / The dynamics of use of land in urban and agricultural areas has led to destruction and fragmentation of ecosystems. It has been related to the increase of susceptibility of natural populations to extinction due to increase of isolation between populations and reduction of population size. To evaluate the effect of the recent habitat fragmentation on the genetic diversity of natural populations, we will analyze the diversity and genetic structure of populations of the wooly mouse opossum Micoureus paraguayanus (Marsupialia: Didelphimorphia) in the Parque Estadual Morro do Diabo (SP) and in bush fragments in its surroundings. For this purpose, we used the control region (D-Loop) to examine population structure and dynamics in fragmented forest habitats. We found low values of haplotypic and nucleotidic diversity when compared to values from previous works with marsupials in fragmented areas. We found values of diversity of 0.28 and 0.0022% respectively. Besides that, there was a correlation between continuous cultivated lands distance and number of exclusives haplotypes. The AMOVA test showed no genetic structure between fragments, however, Fst values indicated significant genetic differentiation to Santa Tereza and Ponte Branca when compared with all the others fragments. These are between the smallest areas evaluated in this study and the differentiation indicates that the recent fragmentation suffered by these patches could be responsible for the changes in the genetic composition of these populations. / A dinâmica de uso da terra em áreas urbanas e rurais tem levado à fragmentação de ecossistemas e suas conseqüências têm sido relacionadas ao aumento da susceptibilidade de populações naturais à extinção devido à redução do tamanho populacional e ao aumento do isolamento por distância entre populações. Para avaliar os efeitos que a fragmentação recente de habitat possui sobre a diversidade genética das populações naturais, nós analisamos a diversidade e estrutura genética do marsupial Micoureus paraguayanus em fragmentos remanescentes de Floresta Estacional Semi-Decidual na região do Pontal do Paranapanema (SP) através da análise da região controle (D-Loop) do DNA mitocondrial. Foram encontrados valores baixos para as diversidades haplotípica e nucleotídica quando comparados à outros valores citados na literatura para populações de outras espécies de marsupiais em declínio. Nós encontramos valores de diversidades haplotípica e nucleotídica de 0.28 e 0.0022% respectivamente. Além disso, foi encontrada uma correlação entre a distancia agropastoril contínua e o numero de haplótipos exclusivos nos fragmentos amostrados para este estudo. O teste AMOVA não detectou estruturação genética entre fragmentos, todavia, os valores de Fst mostram diferenciação significativa dos fragmentos Santa Tereza e Ponte Branca em relação aos demais. Estes estão entre os menores e mais alterados fragmentos avaliados e a sua diferenciação indica que o processo recente de fragmentação (cerca de 60 anos) já pode ter sido o responsável por mudanças na composição genética da população.
27

New Specimens of Sparassodonta (Mammalia, Metatheria) from Chile and Bolivia

Engelman, Russell K. January 2018 (has links)
No description available.

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