scholarly journals Extensive Genetic Connectivity and Historical Persistence Are Features of Two Widespread Tree Species in the Ancient Pilbara Region of Western Australia

Genes ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 863
Author(s):  
Heidi M. Nistelberger ◽  
Rachel M. Binks ◽  
Stephen van Leeuwen ◽  
David J. Coates ◽  
Shelley L. McArthur ◽  
...  

Phylogeographic studies can be used as a tool to understand the evolutionary history of a landscape, including the major drivers of species distributions and diversity. Extensive research has been conducted on phylogeographic patterns of species found in northern hemisphere landscapes that were affected by glaciations, yet the body of literature for older, unaffected landscapes is still underrepresented. The Pilbara region of north-western Australia is an ancient and vast landscape that is topographically complex, consisting of plateaus, gorges, valleys, and ranges, and experiences extreme meteorological phenomena including seasonal cyclonic activity. These features are expected to influence patterns of genetic structuring throughout the landscape either by promoting or restricting the movement of pollen and seed. Whilst a growing body of literature exists for the fauna endemic to this region, less is known about the forces shaping the evolution of plant taxa. In this study we investigate the phylogeography of two iconic Pilbara tree species, the Hamersley Bloodwood (Corymbia hamersleyana) and Western Gidgee (Acacia pruinocarpa), by assessing patterns of variation and structure in several chloroplast DNA regions and nuclear microsatellite loci developed for each species. Gene flow was found to be extensive in both taxa and there was evidence of long-distance seed dispersal across the region (pollen to seed ratios of 6.67 and 2.96 for C. hamersleyana and A. pruinocarpa, respectively), which may result from flooding and strong wind gusts associated with extreme cyclonic activity. Both species possessed high levels of cpDNA genetic diversity in comparison to those from formerly glaciated landscapes (C. hamersleyana = 14 haplotypes, A. pruinocarpa = 37 haplotypes) and showed evidence of deep lineage diversification occurring from the late Miocene, a time of intensifying aridity in this landscape that appears to be a critical driver of evolution in Pilbara taxa. In contrast to another study, we did not find evidence for topographic features acting as refugia for the widely sampled C. hamersleyana.

2019 ◽  
Vol 110 (5) ◽  
pp. 587-600
Author(s):  
A Millie Burrell ◽  
Jeffrey H R Goddard ◽  
Paul J Greer ◽  
Ryan J Williams ◽  
Alan E Pepper

Abstract Globally, a small number of plants have adapted to terrestrial outcroppings of serpentine geology, which are characterized by soils with low levels of essential mineral nutrients (N, P, K, Ca, Mo) and toxic levels of heavy metals (Ni, Cr, Co). Paradoxically, many of these plants are restricted to this harsh environment. Caulanthus ampexlicaulis var. barbarae (Brassicaceae) is a rare annual plant that is strictly endemic to a small set of isolated serpentine outcrops in the coastal mountains of central California. The goals of the work presented here were to 1) determine the patterns of genetic connectivity among all known populations of C. ampexlicaulis var. barbarae, and 2) estimate contemporary effective population sizes (Ne), to inform ongoing genomic analyses of the evolutionary history of this taxon, and to provide a foundation upon which to model its future evolutionary potential and long-term viability in a changing environment. Eleven populations of this taxon were sampled, and population-genetic parameters were estimated using 11 nuclear microsatellite markers. Contemporary effective population sizes were estimated using multiple methods and found to be strikingly small (typically Ne < 10). Further, our data showed that a substantial component of genetic connectivity of this taxon is not at equilibrium, and instead showed sporadic gene flow. Several lines of evidence indicate that gene flow between isolated populations is maintained through long-distance seed dispersal (e.g., >1 km), possibly via zoochory.


2021 ◽  
Author(s):  
◽  
Sebastian Logan

<p>An effective investigation of the underlying ecological processes that shape genetic diversity and connectivity typically requires comparisons among phylogeographic studies of multiple species. Phylogeographic studies of New Zealand’s coastal marine benthos have historically relied on post hoc speculation rather than directed research questions to investigate ecological processes. There has also been a lack of studies on direct developing marine molluscs. Direct developers are expected to have a low potential for dispersal and thus show a pattern of genetic isolation by distance across their distributions. Recent research indicates that this assumption may frequently be violated by instances of long distance dispersal/translocation. The oyster borer (Haustrum scobina) is an endemic direct-developing marine mollusc found in high abundances at rocky intertidal environments across the entirety of New Zealand. This distribution and life history makes H. scobina an ideal target to study genetic connectivity in a species expected to show low realised dispersal and high population genetic structuring. This thesis research used 379 new DNA sequences from the mitochondrial gene cytochrome c oxidase subunit 1 (COI) to investigate the phylogeography of H. scobina across the southern North Island. In addition 16 new COI sequences were inadvertently sequenced from the morphologically similar congener Haustrum albomarginatum. Results from both species support the recently proposed division of H. scobina and H. albomarginatum as separate species. H. scobina populations show significant geographic structure and a lack of haplotype diversity across the south-eastern North Island concordant with results of another previous study of a direct developer. This finding suggests that ecological processes may be producing similar population genetic structures for direct developers generally. Contrast between high and low haplotype diversities in northern and southern H. scobina populations respectively, indicates that southern H. scobina populations may have originated via recolonisation from northern populations following a range contraction during the Last Glacial Maximum. Evidence of multiple long distance dispersal/translocation events was found indicating that long distance dispersal via rafting and/or inadvertent human-mediated translocations may have occurred frequently. Results are then discussed with a view to inform further research in to New Zealand direct developers.</p>


2021 ◽  
Author(s):  
◽  
Sebastian Logan

<p>An effective investigation of the underlying ecological processes that shape genetic diversity and connectivity typically requires comparisons among phylogeographic studies of multiple species. Phylogeographic studies of New Zealand’s coastal marine benthos have historically relied on post hoc speculation rather than directed research questions to investigate ecological processes. There has also been a lack of studies on direct developing marine molluscs. Direct developers are expected to have a low potential for dispersal and thus show a pattern of genetic isolation by distance across their distributions. Recent research indicates that this assumption may frequently be violated by instances of long distance dispersal/translocation. The oyster borer (Haustrum scobina) is an endemic direct-developing marine mollusc found in high abundances at rocky intertidal environments across the entirety of New Zealand. This distribution and life history makes H. scobina an ideal target to study genetic connectivity in a species expected to show low realised dispersal and high population genetic structuring. This thesis research used 379 new DNA sequences from the mitochondrial gene cytochrome c oxidase subunit 1 (COI) to investigate the phylogeography of H. scobina across the southern North Island. In addition 16 new COI sequences were inadvertently sequenced from the morphologically similar congener Haustrum albomarginatum. Results from both species support the recently proposed division of H. scobina and H. albomarginatum as separate species. H. scobina populations show significant geographic structure and a lack of haplotype diversity across the south-eastern North Island concordant with results of another previous study of a direct developer. This finding suggests that ecological processes may be producing similar population genetic structures for direct developers generally. Contrast between high and low haplotype diversities in northern and southern H. scobina populations respectively, indicates that southern H. scobina populations may have originated via recolonisation from northern populations following a range contraction during the Last Glacial Maximum. Evidence of multiple long distance dispersal/translocation events was found indicating that long distance dispersal via rafting and/or inadvertent human-mediated translocations may have occurred frequently. Results are then discussed with a view to inform further research in to New Zealand direct developers.</p>


2015 ◽  
Vol 31 (5) ◽  
pp. 437-447 ◽  
Author(s):  
S. M. Ganzhorn ◽  
W. W. Thomas ◽  
F. A. Gaiotto ◽  
J. D. Lewis

Abstract:Habitat fragmentation may lead to spatial genetic structuring of plant populations, but the magnitude of this effect differs among species. In this study, the effects of fragmentation on spatial genetic structure ofManilkara maxima, an ecologically important tree species endemic to the Atlantic forest of southern Bahia, Brazil, were examined. To address this issue, 222 individuals were sampled across two large-forest sites (200 and 400 ha) and one site comprising eight small fragments (5, 10 and 25 ha) roughly 35 y old. Five microsatellite loci were used. In general,M. maximaexhibited limited genetic structuring within and across the sites examined. At the landscape scale, genetic structure was not shaped by isolation by distance. Within individual sites, weak to moderate genetic structure was observed for both adults and saplings, which represented pre- and post-fragmentation, respectively. Sapling genetic structure did not clearly vary among the study sites, suggesting fragmentation has not affected spatial genetic structure. High levels of migration were observed, which would help maintain genetic connectivity. Taken together, these results suggestM. maxima, a long-lived tree that naturally occurs in low densities, may have limited spatial genetic structuring both within and across forest patches.


2020 ◽  
Vol 5 (3 And 4) ◽  
pp. 155-160
Author(s):  
Mohsen Aghapoor ◽  
◽  
Babak Alijani Alijani ◽  
Mahsa Pakseresht-Mogharab ◽  
◽  
...  

Background and Importance: Spondylodiscitis is an inflammatory disease of the body of one or more vertebrae and intervertebral disc. The fungal etiology of this disease is rare, particularly in patients without immunodeficiency. Delay in diagnosis and treatment of this disease can lead to complications and even death. Case Presentation: A 63-year-old diabetic female patient, who had a history of spinal surgery and complaining radicular lumbar pain in both lower limbs with a probable diagnosis of spondylodiscitis, underwent partial L2 and complete L3 and L4 corpectomy and fusion. As a result of pathology from tissue biopsy specimen, Aspergillus fungi were observed. There was no evidence of immunodeficiency in the patient. The patient was treated with Itraconazole 100 mg twice a day for two months. Pain, neurological symptom, and laboratory tests improved. Conclusion: The debridement surgery coupled with antifungal drugs can lead to the best therapeutic results.


Somatechnics ◽  
2015 ◽  
Vol 5 (1) ◽  
pp. 88-103 ◽  
Author(s):  
Kalindi Vora

This paper provides an analysis of how cultural notions of the body and kinship conveyed through Western medical technologies and practices in Assisted Reproductive Technologies (ART) bring together India's colonial history and its economic development through outsourcing, globalisation and instrumentalised notions of the reproductive body in transnational commercial surrogacy. Essential to this industry is the concept of the disembodied uterus that has arisen in scientific and medical practice, which allows for the logic of the ‘gestational carrier’ as a functional role in ART practices, and therefore in transnational medical fertility travel to India. Highlighting the instrumentalisation of the uterus as an alienable component of a body and subject – and therefore of women's bodies in surrogacy – helps elucidate some of the material and political stakes that accompany the growth of the fertility travel industry in India, where histories of privilege and difference converge. I conclude that the metaphors we use to structure our understanding of bodies and body parts impact how we imagine appropriate roles for people and their bodies in ways that are still deeply entangled with imperial histories of science, and these histories shape the contemporary disparities found in access to medical and legal protections among participants in transnational surrogacy arrangements.


Somatechnics ◽  
2017 ◽  
Vol 7 (2) ◽  
pp. 288-303
Author(s):  
Michael Connors Jackman

This article investigates the ways in which the work of The Body Politic (TBP), the first major lesbian and gay newspaper in Canada, comes to be commemorated in queer publics and how it figures in the memories of those who were involved in producing the paper. In revisiting a critical point in the history of TBP from 1985 when controversy erupted over race and racism within the editorial collective, this discussion considers the role of memory in the reproduction of whiteness and in the rupture of standard narratives about the past. As the controversy continues to haunt contemporary queer activism in Canada, the productive work of memory must be considered an essential aspect of how, when and for what reasons the work of TBP comes to be commemorated. By revisiting the events of 1985 and by sifting through interviews with individuals who contributed to the work of TBP, this article complicates the narrative of TBP as a bluntly racist endeavour whilst questioning the white privilege and racially-charged demands that undergird its commemoration. The work of producing and preserving queer history is a vital means of challenging the intentional and strategic erasure of queer existence, but those who engage in such efforts must remain attentive to the unequal terrain of social relations within which remembering forms its objects.


2019 ◽  
Vol 3 (1-2) ◽  
pp. 103-124
Author(s):  
Gemma Tulud Cruz

Christian missionaries played an important role in the Australian nation building that started in the nineteenth century. This essay explores the multifaceted and complex cultural encounters in the context of two aboriginal missions in Australia in the nineteenth century. More specifically, the essay explores the New Norcia mission in Western Australia in 1846-1900 and the Lutheran mission in South Australia in 1838-1853. The essay begins with an overview of the history of the two missions followed by a discussion of the key faces of the cultural encounters that occurred in the course of the missions. This is followed by theological reflections on the encounters in dialogue with contemporary theology, particularly the works of Robert Schreiter.


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