scholarly journals Evidence of Countergradient Variation in Growth of Spotted Gars from Core and Peripheral Populations

2015 ◽  
Vol 144 (4) ◽  
pp. 837-850 ◽  
Author(s):  
Solomon R. David ◽  
Richard S. Kik ◽  
James S. Diana ◽  
Edward S. Rutherford ◽  
Michael J. Wiley
2011 ◽  
Vol 5 (3) ◽  
pp. 337-364
Author(s):  
Kristin Norget

This article explores new political practices of the Roman Catholic Church by means of a close critical examination of the beatification of the Martyrs of Cajonos, two indigenous men from the Mexican village of San Francisco Cajonos, Oaxaca, in 2002. The Church’s new strategy to promote an upsurge in canonizations and beatifications forms part of a “war of images,” in Serge Gruzinski’s terms, deployed to maintain apparently peripheral populations within the Church’s central paternalistic fold of social and moral authority and influence, while at the same time as it must be seen to remain open to local cultures and realities. In Oaxaca and elsewhere, this ecclesiastical technique of “emplacement” may be understood as an attempt to engage indigenous-popular religious sensibilities and devotion to sacred images while at the same time implicitly trying to contain them, weaving their distinct local historical threads seamlessly into the fabric of a global Catholic history.


Heredity ◽  
2021 ◽  
Author(s):  
Axel Jensen ◽  
Mette Lillie ◽  
Kristofer Bergström ◽  
Per Larsson ◽  
Jacob Höglund

AbstractThe use of genetic markers in the context of conservation is largely being outcompeted by whole-genome data. Comparative studies between the two are sparse, and the knowledge about potential effects of this methodology shift is limited. Here, we used whole-genome sequencing data to assess the genetic status of peripheral populations of the wels catfish (Silurus glanis), and discuss the results in light of a recent microsatellite study of the same populations. The Swedish populations of the wels catfish have suffered from severe declines during the last centuries and persists in only a few isolated water systems. Fragmented populations generally are at greater risk of extinction, for example due to loss of genetic diversity, and may thus require conservation actions. We sequenced individuals from the three remaining native populations (Båven, Emån, and Möckeln) and one reintroduced population of admixed origin (Helge å), and found that genetic diversity was highest in Emån but low overall, with strong differentiation among the populations. No signature of recent inbreeding was found, but a considerable number of short runs of homozygosity were present in all populations, likely linked to historically small population sizes and bottleneck events. Genetic substructure within any of the native populations was at best weak. Individuals from the admixed population Helge å shared most genetic ancestry with the Båven population (72%). Our results are largely in agreement with the microsatellite study, and stresses the need to protect these isolated populations at the northern edge of the distribution of the species.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
H. De Kort ◽  
J. G. Prunier ◽  
S. Ducatez ◽  
O. Honnay ◽  
M. Baguette ◽  
...  

AbstractUnderstanding how biological and environmental factors interactively shape the global distribution of plant and animal genetic diversity is fundamental to biodiversity conservation. Genetic diversity measured in local populations (GDP) is correspondingly assumed representative for population fitness and eco-evolutionary dynamics. For 8356 populations across the globe, we report that plants systematically display much lower GDP than animals, and that life history traits shape GDP patterns both directly (animal longevity and size), and indirectly by mediating core-periphery patterns (animal fecundity and plant dispersal). Particularly in some plant groups, peripheral populations can sustain similar GDP as core populations, emphasizing their potential conservation value. We further find surprisingly weak support for general latitudinal GDP trends. Finally, contemporary rather than past climate contributes to the spatial distribution of GDP, suggesting that contemporary environmental changes affect global patterns of GDP. Our findings generate new perspectives for the conservation of genetic resources at worldwide and taxonomic-wide scales.


Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1385-1395
Author(s):  
Claus Vogl ◽  
Aparup Das ◽  
Mark Beaumont ◽  
Sujata Mohanty ◽  
Wolfgang Stephan

Abstract Population subdivision complicates analysis of molecular variation. Even if neutrality is assumed, three evolutionary forces need to be considered: migration, mutation, and drift. Simplification can be achieved by assuming that the process of migration among and drift within subpopulations is occurring fast compared to mutation and drift in the entire population. This allows a two-step approach in the analysis: (i) analysis of population subdivision and (ii) analysis of molecular variation in the migrant pool. We model population subdivision using an infinite island model, where we allow the migration/drift parameter 0398; to vary among populations. Thus, central and peripheral populations can be differentiated. For inference of 0398;, we use a coalescence approach, implemented via a Markov chain Monte Carlo (MCMC) integration method that allows estimation of allele frequencies in the migrant pool. The second step of this approach (analysis of molecular variation in the migrant pool) uses the estimated allele frequencies in the migrant pool for the study of molecular variation. We apply this method to a Drosophila ananassae sequence data set. We find little indication of isolation by distance, but large differences in the migration parameter among populations. The population as a whole seems to be expanding. A population from Bogor (Java, Indonesia) shows the highest variation and seems closest to the species center.


Botany ◽  
2014 ◽  
Vol 92 (5) ◽  
pp. 340-347 ◽  
Author(s):  
Peter Lesica

Populations at the periphery of a species range are thought to be less viable than those in the center because they are at the limit of their ecological tolerances. Plant population viability is determined primarily by mortality and recruitment, thus knowing differences in vital rates between central and peripheral populations is key to understanding range limits. Silene spaldingii S. Watson is a long-lived iteroparous plant that occurs throughout the eastern Columbia Plateau region of eastern Washington and adjacent Idaho and Oregon and is disjunct in northwest Montana. I recorded the fate of mapped S. spaldingii plants annually for 10 years in four populations, two from eastern Washington and two from Montana. Recruitment averaged three times higher and relatively constant at two central populations in Washington compared with two peripheral sites in Montana. Mortality was three times higher at one of the central populations compared with the remaining three sites due to vole predation. Vole activity was observed at the second central population but came too late in the study to be certain that it resulted in mortality. Vole predation was not observed in the peripheral populations. My results suggest that peripheral populations of S. spaldingii may only be able to persist as long as predation or other sources of mortality remain low and that intrinsic low and variable recruitment rates coupled with predation may help define the eastern range margin of this species.


Author(s):  
Hanqing Tang ◽  
Demei Hu ◽  
Chao Zhang ◽  
Juan Yang ◽  
Mengda Xiang ◽  
...  

The differentiation of reproductive characteristics not only exists between different populations, but also may exist within populations. In this work, the differences between the central and peripheral populations were experimentally compared and analyzed in terms of biodiversity index, plant traits, anthesis, pollen germination, floral visitors, seed setting rate, and ploidy. The results showed that the diversity and richness of other plant species, in the central population were significantly lower than those in the peripheral population, but the plant density was much higher than in the peripheral population. The plant anatomical traits, anthesis, pollen germination, floral visitors, seed setting rate, and ploidy were significantly different between central population and peripheral populations. The term increasing rate (IR) is proposed as a means of comparing morphologies in different organs. IR differences in vegetative characteristics were more stable, while those in reproductive characteristics differed significantly. For the central population, the effect of the intraspecific reproductive competition and pollinator selection on plants may significant, and morphology was differentiated in terms of reproductive characteristics. Plants in the peripheral populations were visited by many more pollinators than in the central population, and all pollinators visited infrequently. The reproductive characteristics of plants in the peripheral populations may therefore only be weakly affected by pollinator selection. The reproductive characteristics of plants in the peripheral population may weakly affected by the selection of pollinators and the variation was small. In conclusion, morphological differentiation among the different populations was associated with differences in vegetative and reproductive characteristics.


2017 ◽  
Vol 7 (20) ◽  
pp. 8363-8378 ◽  
Author(s):  
Esteban Botero-Delgadillo ◽  
Verónica Quirici ◽  
Yanina Poblete ◽  
Élfego Cuevas ◽  
Sylvia Kuhn ◽  
...  

2011 ◽  
Vol 278 (1721) ◽  
pp. 3050-3059 ◽  
Author(s):  
Ulrich G. Mueller ◽  
Alexander S. Mikheyev ◽  
Scott E. Solomon ◽  
Michael Cooper

Tropical leaf-cutter ants cultivate the fungus Attamyces bromatificus in a many-to-one, diffuse coevolutionary relationship where ant and fungal partners re-associate frequently over time. To evaluate whether ant– Attamyces coevolution is more specific (tighter) in peripheral populations, we characterized the host-specificities of Attamyces genotypes at their northern, subtropical range limits (southern USA, Mexico and Cuba). Population-genetic patterns of northern Attamyces reveal features that have so far not been observed in the diffusely coevolving, tropical ant– Attamyces associations. These unique features include (i) cases of one-to-one ant– Attamyces specialization that tighten coevolution at the northern frontier; (ii) distributions of genetically identical Attamyces clones over large areas (up to 81 000 km 2 , approx. the area of Ireland, Austria or Panama); (iii) admixture rates between Attamyces lineages that appear lower in northern than in tropical populations; and (iv) long-distance gene flow of Attamyces across a dispersal barrier for leaf-cutter ants (ocean between mainland North America and Cuba). The latter suggests that Attamyces fungi may occasionally disperse independently of the ants, contrary to the traditional assumption that Attamyces fungi depend entirely on leaf-cutter queens for dispersal. Peripheral populations in Argentina or at mid-elevation sites in the Andes may reveal additional regional variants in ant– Attamyces coevolution. Studies of such populations are most likely to inform models of coextinctions of obligate mutualistic partners that are doubly stressed by habitat marginality and by environmental change.


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