Genetic structure of Pyrenophora teres populations determined with random amplified polymorphic DNA markers

1994 ◽  
Vol 72 (7) ◽  
pp. 915-923 ◽  
Author(s):  
Tobin L. Peever ◽  
Michael G. Milgroom
Keyword(s):  
New York ◽  
Genetic Structure ◽  
Random Amplified Polymorphic Dna ◽  
Geographic Origin ◽  
Allelic Diversity ◽  
Allele Frequencies ◽  
German Population ◽  
Pyrenophora Teres ◽  
Gametic Disequilibrium ◽  
The North

The genetic structure of Pyrenophora teres, an ascomycete fungus that causes net blotch of barley, was examined using random amplified polymorphic DNA (RAPD) markers. Twenty-seven random oligonucleotide primers were screened against DNA from 16 isolates of P. teres of diverse geographic origin. Five primers gave scorable, reproducible DNA products (bands) suitable for population genetic studies. Genetic analyses of bands produced by two of the primers revealed single locus segregation in three of four crosses, indicating that these RAPDs can be interpreted as alleles at genetic loci. Allele frequencies were determined for 10 putative RAPD loci from five primers in 22–35 isolates of P. teres sampled from each of five geographically separated populations in Canada, Germany, and the U.S.A. Eight RAPD loci were polymorphic in at least one population and two loci were monomorphic in all five populations. Variation in allele frequencies (allelic diversity) among the five populations was partitioned into within- and among-population components using Nei's GST. A GST value of 0.46 was obtained among all populations indicating that approximately 46% of the total genetic variability detected was due to differentation among populations compared with 54% within populations. A GST value of 0.33 was obtained among the North American populations only. From five to nine multilocus genotypes were found in each population. Nine genotypes occurred exclusively in the German population and four exclusively in the New York population. The other populations had one or two unique genotypes. Gametic disequilibrium values (nonrandom associations of RAPD loci) were calculated among all pairs of polymorphic loci within each population. Eleven of 49 values were significantly different from 0 (P < 0.05); 8 of the 11 significant gametic disequilibrium values occurred in the New York population. Highly significant gametic disequilibrium was detected between the same two RAPD loci in three different populations, suggesting that these loci are genetically linked. Two different multilocus analyses revealed that the genetic structures of the Alberta, North Dakota, and German populations but not the New York population were consistent with random sexual reproduction occurring in these populations. Key words: polymerase chain reaction, population genetics, fungi, genetic differentiation.

scholarly journals The assessment of the genetic structure of bush snail (Fruticicola fruticum) populations based on the nonspecific esterases loci

2019 ◽  
Vol 17 (4) ◽  
pp. 15-26
Author(s):  
Eduard A. Snegin ◽  
Elena A. Snegina ◽  
Olesya Yu. Artemchuk
Keyword(s):  
Genetic Structure ◽  
Isolation By Distance ◽  
Allelic Diversity ◽  
Principal Component ◽  
Forest Steppe ◽  
North Caucasus ◽  
Relict Species ◽  
The North ◽  
Central Russian Upland ◽  
Parametric Statistics

Using the polymorphic esterases loci, the genetic structure of the gastropod mollusk Fruticicola (Bradybaena) fruticum Мll., most of which lives in the south of the Central Russian Upland, was studied. For comparison, the samples were taken from the Romania, the North Caucasus, the Ural and the Vyatka regions. A total of the 1668 individuals were investigated. Of the 28 studied populations in 11 (39.3%), there was significant shortage of the heterozygotes. The level of the expected heterozygosity fluctuated in the range He = 0.1160.454. Using the non-parametric statistics (Chao1-bc method and 1st order jackknife method), the populations with potentially high and low diversity of the multilocus genotypes were identified. The indicators of the genetic disunity between populations averaged st = 0.276, Fst = 0.292. The principal component analysis and the Mantel correlation criterion Rм = 0.007 showed the absence of a reliable relationship between the geographical and genetic distance between populations, which indicates a violation of the isolation model by distance and confirms the thesis put forward by us that the urbanized forest-steppe landscape disrupts the natural migration processes, leads to the strong isolation and the genetic drift in the snail populations. At the same time, the phenomenon of increasing the degree of division of the populations against the background of reduced the allelic diversity, noted by us in many groups of bush snails, can be regarded as a shift in genetic equilibrium towards an increase in the interpopupulation diversity (according to the Wright model). The revealed absence of the effect of isolation by distance can be a consequence of the action of the stabilizing natural selection. The assumption of the dependence of the esterase alleles frequencies in the bush snail populations on the genetic (biochemical) characteristics of the food objects was proposed. The effective size, calculated using the Slatkin formula turned out to be comparable with the background, adventive and relict species of the terrestrial mollusks living in the study area (Ne = 2.27.6).

scholarly journals Molecular characterization of bulgarian livestock genetic resources, II: Microsatelite variation within and among Bulgarian cattle breeds

2007 ◽  
Vol 23 (5-6-1) ◽  
pp. 227-242 ◽  
Author(s):  
A. Teneva ◽  
E. Todorovska ◽  
N. Tyufekchiev ◽  
A. Stella ◽  
P. Boettcher ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Genetic Resources ◽  
Molecular Characterization ◽  
Allelic Diversity ◽  
Allele Frequencies ◽  
Cattle Breeds ◽  
High Level

This study was undertaken to determine the genetic structure and the diversity among 2 local cattle breeds from Bulgaria, the Rhodope Shorthorn and Grey cattle. A panel of 11 microsatellites was used for the evaluation. For these loci, allele frequencies, heterozygosity, HWE, genetic disequilibrium, genic differentiation were determined. Both populations displayed a relatively high level of genetic variation as estimated by allelic diversity and heterozygosity. Heterozygosities ranged from 0.5424 /SPS 115/ to 0.8983 /TGLA 227/ for the Rhodope population and 0.6333 /TGLA 53/ to 0.9333 /TGLA227/ for Grey cattle, with similar average values for the two groups - 0.7858 and 0.7757. These results clearly suggest that these breeds are suitable to preserve as a genetic resources.

Mafias on the Move

2011 ◽  
Author(s):  
Federico Varese
Keyword(s):  
United States ◽  
New York ◽  
Organized Crime ◽  
The United States ◽  
The West ◽  
Market Expansion ◽  
The North ◽  
Economic Transformations ◽  
At Will

Organized crime is spreading like a global virus as mobs take advantage of open borders to establish local franchises at will. That at least is the fear, inspired by stories of Russian mobsters in New York, Chinese triads in London, and Italian mafias throughout the West. As this book explains, the truth is more complicated. The author has spent years researching mafia groups in Italy, Russia, the United States, and China, and argues that mafiosi often find themselves abroad against their will, rather than through a strategic plan to colonize new territories. Once there, they do not always succeed in establishing themselves. The book spells out the conditions that lead to their long-term success, namely sudden market expansion that is neither exploited by local rivals nor blocked by authorities. Ultimately the inability of the state to govern economic transformations gives mafias their opportunity. In a series of matched comparisons, the book charts the attempts of the Calabrese 'Ndrangheta to move to the north of Italy, and shows how the Sicilian mafia expanded to early twentieth-century New York, but failed around the same time to find a niche in Argentina. The book explains why the Russian mafia failed to penetrate Rome but succeeded in Hungary. A pioneering chapter on China examines the challenges that triads from Taiwan and Hong Kong find in branching out to the mainland. This book is both a compelling read and a sober assessment of the risks posed by globalization and immigration for the spread of mafias.

Die Konstruktion von Natur – Central Park neu besichtigt | The Construction of Nature – Central Park Revisited

2005 ◽  
Vol 156 (8) ◽  
pp. 288-296
Author(s):  
Vittorio Magnago Lampugnani
Keyword(s):  
New York ◽  
Hudson River ◽  
The United States ◽  
Central Park ◽  
Housing Developments ◽  
Hudson River School ◽  
The North ◽  
Man And Nature ◽  
The 19Th Century ◽  
The Relationship

In the first half of the 19th century scientific philosophers in the United States, such as Emerson and Thoreau, began to pursue the relationship between man and nature. Painters from the Hudson River School discovered the rural spaces to the north of New York and began to celebrate the American landscape in their paintings. In many places at this time garden societies were founded, which generated widespread support for the creation of park enclosures While the first such were cemeteries with the character of parks, housing developments on the peripheries of towns were later set in generous park landscapes. However, the centres of the growing American cities also need green spaces and the so-called «park movement»reached a first high point with New York's Central Park. It was not only an experimental field for modern urban elements, but even today is a force of social cohesion.

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