OPUS: Open Ulethbridge Scholarship
Open ULeth Scholarship (OPUS) is the University of Lethbridge's open access research repository. It contains a collection of materials related to research and teaching produced by the academic community.
Self-archiving your research in OPUS is one way to meet Open Access policies of granting agencies. It is important to retain your final, post-peer-reviewed drafts for submission to OPUS, as this is often the only version publishers will allow to be archived. Click here for information on the U of L Open Access Policy.
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Biophysical characterization of honey bee virus untranslated regions
(Lethbridge, Alta. : University of Lethbridge, Dept. of Chemistry and Biochemistry, 2024) Letain, Jenna M.; University of Lethbridge. Faculty of Arts and Science; Patel, Trushar R.
Over the past two decades, honey bee colony losses have become a serious and widespread issue. Many factors contribute to these losses, but one major driver is viruses. Sacbrood virus and deformed wing virus are found globally and can cause detrimental effects to honey bee colonies. These viruses have a long, single-stranded genome of ribonucleic acid (RNA) flanked by structured untranslated regions. Although noncoding, these regions play important roles in the viral life cycle. While untranslated regions have been studied extensively in other viruses, there is a research gap for honey bee viruses. This thesis focuses on the biophysical characterization of the untranslated regions of these two common honey bee viruses. Small-angle X-ray scattering and computational modelling elucidated low and high-resolution three-dimensional structures for the viral untranslated regions. Functional assays revealed that the sacbrood virus 5′ untranslated region acts as an internal ribosome entry site capable of initiating translation. Furthermore, immunoprecipitation pull-down assays identified potential RNA-binding proteins that interact with the sacbrood virus untranslated regions. Altogether, this thesis provides foundational insights into the characteristics of the untranslated regions of sacbrood virus and deformed wing virus, guiding future research in this field.
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The endocast of the Night Parrot (Pezoporus occidentalis) reveals insights into its sensory ecology and the evolution of nocturnality in birds
(Nature Portfolio, 2020) Iwaniuk, Andrew N.; Keirnan, Aubrey R.; Janetzki, Heather; Mardon, Karine; Murphy, Stephen; Leseberg, Nicholas P.; Weisbecker, Vera
he Night Parrot (Pezoporus occidentalis) is a rare, nocturnal parrot species that has largely escaped scientific investigation due to its behaviour and habitat preferences. Recent field studies have revealed some insights into Night Parrot behaviour, but nothing is known of its sensory abilities. Here, we used μCT scans of an intact Night Parrot specimen to determine if its visual system shares similarities with other nocturnal species. The endocast of the Night Parrot revealed relatively small optic lobes and optic foramina, especially compared with closely related grass parakeets, but no apparent differences in orbit dimensions. Our data suggests that the Night Parrot likely has lower visual acuity than most other parrots, including its congener, the Eastern Ground Parrot (P. wallicus). We propose that the visual system of the Night Parrot might represent a compromise between the need to see under low light conditions and the visual acuity required to detect predators, forage, and fly. Based on the endocast and optic foramen measurements, the Night Parrot fits into a common pattern of decreased retinal input to the optic lobes in birds that should be explored more thoroughly in extant and extinct species.
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The evolution of skilled hindlimb movements in birds: a citizen science approach
(2023) Gutiérrez-Ibáñez, Cristián; Amaral-Peçanha, Clara; Iwaniuk, Andrew N.; Wylie, Douglas R.; Baron, Jerome
The ability to manipulate objects with limbs has evolved repeatedly among land tetrapods. Several selective forces have been proposed to explain the emergence of forelimb manipulation, however, work has been largely restricted to mammals, which prevents the testing of evolutionary hypotheses in a comprehensive evolutionary framework. In birds, forelimbs have gained the exclusive function of flight, with grasping transferred predominantly to the beak. In some birds, the feet are also used in manipulative tasks and appear to share some features with manual grasping and prehension in mammals, but this has not been systematically investigated. Here we use large online repositories of photographs and videos to quantify foot manipulative skills across a large sample of bird species (>1000 species). Our results show that a complex interaction between niche, diet and phylogeny drive the evolution of manipulative skill with the feet in birds. Furthermore, we provide strong support for the proposition that an arboreal niche is a key element in the evolution of manipulation in land vertebrates. Our systematic comparison of foot use in birds provides a solid base for understanding morphological and neural adaptations for foot use in birds, and for studying the convergent evolution of manipulative skills in birds and mammals.
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The evolution of mammalian brain size
(American Association for Advancement of Science, 2021) Smaers, J. B.; Rothman, R. S.; Hudson, D. R.; Balanoff, A. M.; Beatty, B.; Dechmann, D. K. N.; de Vries, D.; Dunn, J. C.; Fleagle, J. G.; Gilbert, C. C.; Goswami, A.; Iwaniuk, Andrew N.; Jungers, W. L.; Kerney, M.; Ksepka, D. T.; Manger, P. R.; Mongle, C. S.; Rohlf, F. J.; Smith, N. A.; Soligo, C.; Weisbecker, V.; Safi, K.
Relative brain size has long been considered a reflection of cognitive capacities and has played a fundamental role in developing core theories in the life sciences. Yet, the notion that relative brain size validly represents selection on brain size relies on the untested assumptions that brain-body allometry is restrained to a stable scaling relationship across species and that any deviation from this slope is due to selection on brain size. Using the largest fossil and extant dataset yet assembled, we find that shifts in allometric slope underpin major transitions in mammalian evolution and are often primarily characterized by marked changes in body size. Our results reveal that the largest-brained mammals achieved large relative brain sizes by highly divergent paths. These findings prompt a reevaluation of the traditional paradigm of relative brain size and open new opportunities to improve our understanding of the genetic and developmental mechanisms that influence brain size.
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The cerebellar anatomy of red junglefowl and white leghorn chickens: insights into the effects of domestication on the cerebellum
(Royal Society, 2021) Racicot, Kelsey J.; Popic, Christina; Cunha, Felipe; Wright, Dominic; Henriksen, Christina; Iwaniuk, Andrew N.
Domestication is the process by which wild organisms become adapted for human use. Many phenotypic changes are associated with animal domestication, including decreases in brain and brain region sizes. In contrast with this general pattern, the chicken has a larger cerebellum compared with the wild red junglefowl, but what neuroanatomical changes are responsible for this difference have yet to be investigated. Here, we quantified cell layer volumes, neuron numbers and neuron sizes in the cerebella of chickens and junglefowl. Chickens have larger, more folded cerebella with more and larger granule cells than junglefowl, but neuron numbers and cerebellar folding were proportional to cerebellum size. However, chickens do have relatively larger granule cell layer volumes and relatively larger granule cells than junglefowl. Thus, the chicken cerebellum can be considered a scaled-up version of the junglefowl cerebellum, but with enlarged granule cells. The combination of scaling neuron number and disproportionate enlargement of cell bodies partially supports a recent theory that domestication does not affect neuronal density within brain regions. Whether the neuroanatomical changes we observed are typical of domestication or not requires similar quantitative analyses in other domesticated species and across multiple brain regions.