A comparative study of genetic diversity of populations of Nectria galligena and N. coccinea var. faginata in North America

2002 ◽  
Vol 106 (2) ◽  
pp. 183-193 ◽  
Author(s):  
Franĉoise Plante ◽  
Richard C. Hamelin ◽  
Louis Bernier
Keyword(s):  
Genetic Diversity ◽  
North America ◽  
Comparative Study ◽  
Nectria Galligena

scholarly journals Limited Genetic Diversity in North American Isolates of Phytophthora erythroseptica Pathogenic to Potato Based on RAPD Analysis

Plant Disease ◽  
2005 ◽  
Vol 89 (4) ◽  
pp. 380-384 ◽  
Author(s):  
Rick D. Peters ◽  
Rod J. Clark ◽  
Albert D. Coffin ◽  
Antony V. Sturz ◽  
David H. Lambert ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
North America ◽  
New Brunswick ◽  
Prince Edward Island ◽  
Random Amplified Polymorphic Dna ◽  
Geographic Origin ◽  
The United States ◽  
Vitro Assay ◽  
Phytophthora Erythroseptica

Pink rot of potato (Solanum tuberosum), caused by Phytophthora erythroseptica, is found wherever potatoes are grown, and in the last decade, it has reemerged as an economically important disease in Canada and the United States. A selection of isolates of P. erythroseptica from major potato-growing regions in North America, namely Prince Edward Island and New Brunswick, Canada, and Maine and Idaho, U.S.A., was assessed for genetic diversity with randomly chosen decanucleotide primers which were used to amplify regions of DNA to reveal polymorphisms among templates (random amplified polymorphic DNA [RAPD]). The isolates varied in their geographic origin as well as in their sensitivity to mefenoxam, as determined by an in vitro assay. In three separate RAPD screens (I, II, and III) with 23 isolates of P. erythroseptica chosen from a larger collection, 1,410, 369, and 316 robust, scorable bands were amplified, respectively. However, among the bands amplified in screens I, II, and III, only 3, 1, and 3 bands, respectively, were polymorphic. When three primers yielding polymorphisms were used to screen 106 isolates from Prince Edward Island and New Brunswick, or a representative collection of 32 isolates from Prince Edward Island, New Brunswick, Maine, and Idaho, no major variation was discovered. RAPD markers were not correlated with geographic origin or mefenoxam sensitivity of the isolates. From an evolutionary standpoint, the absence of genetic diversity among the isolates of P. erythroseptica we examined may be attributable to the relatively recent introduction of a small founding population of the pathogen in North America.

Geographic patterns of genetic diversity in North American trees: a continent-wide analysis

2021 ◽  
Author(s):  
Andrew V. Gougherty
Keyword(s):  
Genetic Diversity ◽  
Population Genetics ◽  
North America ◽  
North American ◽  
Tree Species ◽  
Geographic Patterns ◽  
Study Characteristics ◽  
Dispersal Traits ◽  
The Last Glacial Maximum ◽  
The Last Glacial

In the northern hemisphere, many species have been reported to have greater genetic diversity in southern populations than northern populations - ostensibly due to migration northward following the last glacial maximum (LGM). The generality of this pattern, while well-established for some taxa, remains unclear for North American trees. To address this issue, I collected published population genetics data for 73 North American tree species, and tested whether genetic diversity was associated with latitude or longitude and whether geographic trends were associated with dispersal traits, range or study characteristics. I found there were no general geographic patterns in genetic diversity, and the strength of the geographic gradients were not associated with any species or study characteristics. Species in the northern and western regions of North America tended to have more species with genetic diversity that declined with latitude, but most species had no significant trend. This work shows that North American trees have complex, individualistic, patterns of genetic diversity that may negate explanation by any particular dispersal trait or range characteristic.

scholarly journals Genetic diversity, population structure, and effective population size in two yellow bat species in south Texas

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10348
Author(s):  
Austin S. Chipps ◽  
Amanda M. Hale ◽  
Sara P. Weaver ◽  
Dean A. Williams
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
North America ◽  
Wind Energy ◽  
Population Size ◽  
Effective Population Size ◽  
Microsatellite Loci ◽  
South Texas ◽  
Population Substructure ◽  
Effective Population

There are increasing concerns regarding bat mortality at wind energy facilities, especially as installed capacity continues to grow. In North America, wind energy development has recently expanded into the Lower Rio Grande Valley in south Texas where bat species had not previously been exposed to wind turbines. Our study sought to characterize genetic diversity, population structure, and effective population size in Dasypterus ega and D. intermedius, two tree-roosting yellow bats native to this region and for which little is known about their population biology and seasonal movements. There was no evidence of population substructure in either species. Genetic diversity at mitochondrial and microsatellite loci was lower in these yellow bat taxa than in previously studied migratory tree bat species in North America, which may be due to the non-migratory nature of these species at our study site, the fact that our study site is located at a geographic range end for both taxa, and possibly weak ascertainment bias at microsatellite loci. Historical effective population size (NEF) was large for both species, while current estimates of Ne had upper 95% confidence limits that encompassed infinity. We found evidence of strong mitochondrial differentiation between the two putative subspecies of D. intermedius (D. i. floridanus and D. i. intermedius) which are sympatric in this region of Texas, yet little differentiation using microsatellite loci. We suggest this pattern is due to secondary contact and hybridization and possibly incomplete lineage sorting at microsatellite loci. We also found evidence of some hybridization between D. ega and D. intermedius in this region of Texas. We recommend that our data serve as a starting point for the long-term genetic monitoring of these species in order to better understand the impacts of wind-related mortality on these populations over time.

scholarly journals Population structure and demographic history of the chukar partridge Alectoris chukar in China

2013 ◽  
Vol 59 (4) ◽  
pp. 458-474 ◽  
Author(s):  
Sen Song ◽  
Shijie Bao ◽  
Ying Wang ◽  
Xinkang Bao ◽  
Bei An ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
North America ◽  
Demographic History ◽  
Population Expansion ◽  
Northwest China ◽  
Population History ◽  
Extant Species ◽  
History Of ◽  
Chukar Partridge

Abstract Pleistocene climate fluctuations have shaped the patterns of genetic diversity observed in extant species. Although the effects of recent glacial cycles on genetic diversity have been well studied on species in Europe and North America, genetic legacy of species in the Pleistocene in north and northwest of China where glaciations was not synchronous with the ice sheet development in the Northern Hemisphere or or had little or no ice cover during the glaciations’ period, remains poorly understood. Here we used phylogeographic methods to investigate the genetic structure and population history of the chukar partridge Alec-toris chukar in north and northwest China. A 1,152 – 1,154 bp portion of the mtDNA CR were sequenced for all 279 specimens and a total number of 91 haplotypes were defined by 113 variable sites. High levels of gene flow were found and gene flow estimates were greater than 1 for most population pairs in our study. The AMOVA analysis showed that 81% and 16% of the total genetic variability was found within populations and among populations within groups, respectively. The demographic history of chukar was examined using neutrality tests and mismatch distribution analyses and results indicated Late Pleistocene population expansion. Results revealed that most populations of chukar experienced population expansion during 0.027 ? 0.06 Ma. These results are at odds with the results found in Europe and North America, where population expansions occurred after Last Glacial Maximum (LGM, 0.023 to 0.018 Ma). Our results are not consistent with the results from avian species of Tibetan Plateau, either, where species experienced population expansion following the retreat of the extensive glaciation period (0.5 to 0.175 Ma).

A comparative study of community medicine and public health curriculum at medical schools in Iran and North America

2021 ◽  
Vol 10 (1) ◽  
pp. 19-19
Author(s):  
Tahereh Changiz ◽  
Mahasti Alizadeh
Keyword(s):  
Public Health ◽  
North America ◽  
Comparative Study ◽  
General Medicine ◽  
Medical Schools ◽  
The United States ◽  
Community Medicine ◽  
Center Staff ◽  
Health Curriculum ◽  
Spiral Curriculum

Background: Community medicine and public health are the core subjects in medical education. One of the main competencies of general physicians in the national curriculum is having knowledge and skills in health promotion and disease prevention in the health system. Any curriculum revision in community medicine departments needs to incorporate the evidence and use pioneer countries’ experiences in this issue. This study aims to compare community medicine and public health courses in medical schools between Iran and selected universities in North America. Methods: The elements of a community medicine curriculum for medical students were compared in a descriptive-comparative study using the Bereday model. These elements included objectives and competencies, educational strategies, teaching and learning methods, assessment, and educational fields in a community medicine curriculum in Iran and in selected universities in North America. A literature search was conducted in CINAHL, SCOPUS, MEDLINE, Web of Science, EBSCO, and on university websites. Results: Essential aspects of community-based strategies among community medicine and public health curriculum of general medicine in universities in Canada and the United States included a longitudinal approach, training in urban and rural primary care centers, teaching by family physicians and health center staff, a spiral curriculum, focus on social determinants of health, taking of social and cultural histories and social prescriptions, learning teamwork, and using LIC (Longitudinal Integrated Curriculum). Conclusion: The objective of community medicine and public health curriculum in selected North American universities was to prepare general practitioners who work in Level 2 and 3 hospitals and to improve their skills to provide high-quality services to the community. Some of the successful points in the selected universities that could be replicated in Iranian faculties of medicine included using integration strategy, a spiral curriculum, and an LIC approach.

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