Megan J. Osborne

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Successful recovery and sustainability of threatened and exploited species depends in part on retention and maintenance of genetic diversity. Theory indicates that genetic diversity is lost at a rate inversely proportional to the genetically effective population size (N(e)), which is roughly equal to one-half the adult census size (N) in many organisms.(More)
Mitochondrial ND2 sequences were used to investigate the phylogenetic relationships amongst 31 diprotodontid marsupials (kangaroos, wombats, koala, possums, and allies). ND2 sequences were analyzed separately and in conjunction with available 12S rDNA sequences for 22 diprotodontid taxa. Phylogenetic analyses consistently identified monophyly for the(More)
The endangered Rio Grande silvery minnow persists as a remnant population in a highly fragmented and regulated arid-land river system. The species is subject to dramatic annual fluctuations in density. Since 2003, the wild population has been supplemented by hatchery-reared fish. We report on a 12-year (1999-2010) monitoring study of genetic diversity and(More)
A sweepstakes–mismatch process whereby reproduction is poorly coordinated with appropriate resources for larval development and recruitment can result in large variance in reproductive success among individuals and spawning aggregations. This process has been proposed to explain low ratio of genetic effective population size (Ne) to adult census size (N)(More)
Genetic drift is expected to be the predominant evolutionary force in small, fragmented peripheral populations, which can lead to divergent allele frequencies and lowered diversity compared to the core population. Peripheral populations are not considered a high priority for conservation for this reason. However, peripheral populations may possess unique(More)
Climate change will strongly impact aquatic ecosystems particularly in arid and semi-arid regions. Fish-parasite interactions will also be affected by predicted altered flow and temperature regimes, and other environmental stressors. Hence, identifying environmental and genetic factors associated with maintaining diversity at immune genes is critical for(More)
Thorough sampling is necessary to delineate lineage diversity for polytypic "species" such as Cyprinella lutrensis. We conducted extensive mtDNA sampling (cytochrome b and ND4) from the Pecos River, Rio Grande, and South Canadian River, New Mexico. Our study emphasized the Pecos River due to its complex geological history and potential to harbor multiple(More)
Phylogenetic relationships within the possums of the family Petauridae, including their affinities with the family Pseudocheiridae, were inferred from DNA sequences obtained for the mitochondrial ND2 gene (1040 bp) combined with previously published partial 12S rDNA sequences. Short, deep internodes characterize some of the divergences obtained. The(More)
Genetic monitoring tracks changes in measures of diversity including allelic richness, heterozygosity and genetic effective size over time, and has emerged as an important tool for understanding evolutionary consequences of population management. One proposed application of genetic monitoring has been to estimate abundance and its trajectory through time.(More)
The mountain pygmy-possum, Burramys parvus, exists in isolated and fragmented populations in the Australian alps. To examine the degree of interpopulation divergence, mitochondrial cytochrome b and NADH dehydrogenase subunit 2 (NADH2) sequences were obtained from samples representing all populations of B. parvus. Three divergent mitochondrial DNA (mtDNA)(More)