scholarly journals Environmental Selection Pressures Related to Iron Utilization Are Involved in the Loss of the Flavodoxin Gene from the Plant Genome

2015 ◽  
Vol 7 (3) ◽  
pp. 750-767 ◽  
Author(s):  
Juan J. Pierella Karlusich ◽  
Romina D. Ceccoli ◽  
Martín Graña ◽  
Héctor Romero ◽  
Néstor Carrillo
Keyword(s):  
Plant Genome ◽  
Selection Pressures ◽  
Environmental Selection ◽  
Iron Utilization

scholarly journals Climatic niche predicts the landscape structure of locally adaptive standing genetic variation

2019 ◽  
Author(s):  
Vikram E. Chhatre ◽  
Karl C. Fetter ◽  
Andrew V. Gougherty ◽  
Matthew C. Fitzpatrick ◽  
Raju Y. Soolanayakanahally ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Stress Responses ◽  
Latitudinal Gradients ◽  
Intraspecific Diversity ◽  
Climatic Niche ◽  
Selection Pressures ◽  
Balsam Poplar ◽  
Environmental Selection ◽  
Locally Adaptive ◽  
Spatially Varying

AbstractWithin a species’ range, intraspecific diversity in the form of adaptive standing genetic variation (SGV) may be non-randomly clustered into different geographic regions, reflecting the combined effects of historical range movements and spatially-varying natural selection. As a consequence of a patchy distribution of adaptive SGV, populations in different parts of the range are likely to vary in their capacity to respond to changing selection pressures, especially long-lived sessile organisms like forest trees. However, the spatial distribution of adaptive SGV across the landscape is rarely considered when predicting species responses to environmental change. Here, we use a landscape genomics approach to estimate the distribution of adaptive SGV along spatial gradients reflecting the expansion history and contemporary climatic niche of balsam poplar, Populus balsamifera (Salicaceae), a widely distributed forest tree with a transcontinental distribution in North America. By scanning the genome for signatures of spatially varying local adaptation, we estimated how adaptive SGV has been shaped by geographic distance from the rear range edge (expansion history) versus proximity to the current center of the climatic niche (environmental selection). We found that adaptive SGV was strongly structured by the current climatic niche, with surprisingly little importance attributable to historical effects such as migration out of southern refugia. As expected, the effect of the climatic niche on SGV was strong for genes whose expression is responsive to abiotic stress (drought), although genes upregulated under biotic (wounding) stress also contained SGV that followed climatic and latitudinal gradients. The latter result could reflect parallel selection pressures, or co-regulation of functional pathways involved in both abiotic and biotic stress responses. Our study in balsam poplar suggests that clustering of locally adaptive SGV within ranges primarily reflects spatial proximity within the contemporary climatic niche – an important consideration for the design of effective strategies for biodiversity conservation and avoidance of maladaptation under climate change.

scholarly journals Phenotypic Variation in Skull Size and Shape Between Newfoundland and Mainland Populations of North American Black Bears, Ursus americanus

2003 ◽  
Vol 117 (2) ◽  
pp. 236 ◽  
Author(s):  
John A. Virgl ◽  
Shane P. Mahoney ◽  
Kim Mawhinney
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Ursus Americanus ◽  
Population Variation ◽  
Black Bears ◽  
Selection Pressures ◽  
Skull Shape ◽  
Skull Size ◽  
Environmental Selection ◽  
Gape Size

It is well recognized that differences in environmental selection pressures among populations can generate phenotypic divergence in a suite of morphological characteristics and associated life history traits. Previous analysis of mitochondrial DNA and body size have suggested that Black Bears (Ursus americanus) inhabiting the island of Newfoundland represent a different subspecies or ecotype from mainland populations. Assuming that body size covaries positively with skull size, we predicted that skull size would be greater for bears on the island than the mainland, and the distribution of size-related shape components in multivariate space should show a distinct separation between Newfoundland and mainland populations. Measurements of 1080 specimens from Newfoundland, Alberta, New York, and Quebec did not provide unequivocal support for our prediction that skull size in Newfoundland bears would be larger than bears from the mainland populations. After removing ontogenetic effects of skull size, between-population variation in skull shape was greater in females than males, and the analysis significantly separated Newfoundland bears from mainland populations. Explanations for this pattern are numerous, but currently remain hypothetical. Limited covariation between skull size and body size suggests that genetic traits regulating the size of Black Bear skulls are more heritable (i.e., less influenced by environmental selection pressures) than characteristics affecting body size. We hypothesize that if gape size does not limit prey size in solitary terrestrial carnivores, large degrees of among-population variation in body size should be coupled with little covariation in skull size. In general, sexual dimorphism in skull size and shape was marginal for the phenotypic characters measured in our study. We believe that sexual dimorphism in skull size in Black Bears is primarily driven by intrasexual selection in males for increased gape size display, while similarity in skull shape between sexes is associated with the constraints of a temporally-selective, but similar diet.

scholarly journals Simplifying cellulase production by using environmental selection pressures and recycling substrate

2013 ◽  
Vol 34 (4) ◽  
pp. 471-475 ◽  
Author(s):  
Mitchell Lever ◽  
Goen Ho ◽  
Ralf Cord-Ruwisch
Keyword(s):  
Cellulase Production ◽  
Selection Pressures ◽  
Environmental Selection

scholarly journals HABITAT-DEPENDENT SONG DIVERGENCE IN THE LITTLE GREENBUL: AN ANALYSIS OF ENVIRONMENTAL SELECTION PRESSURES ON ACOUSTIC SIGNALS

Evolution ◽  
2002 ◽  
Vol 56 (9) ◽  
pp. 1849-1858 ◽  
Author(s):  
Hans Slabbekoorn ◽  
Thomas B. Smith
Keyword(s):  
Acoustic Signals ◽  
Selection Pressures ◽  
Environmental Selection ◽  
Song Divergence

scholarly journals Behaviors of Homologous Antibiotic Resistance Genes in a Cephalosporin WWTP, Subsequent WWTP and the Receiving River

2021 ◽  
Vol 9 ◽  
Author(s):  
Lei Chen ◽  
Mengyu Zhang ◽  
Daliang Ning ◽  
Joy D Van Nostrand ◽  
Yunfeng Yang ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Relative Abundance ◽  
Resistance Genes ◽  
Antibiotic Production ◽  
Treatment Plant ◽  
Antibiotic Resistance Genes ◽  
Gene Families ◽  
Selection Pressures ◽  
Environmental Selection ◽  
Receiving Stream

High concentrations of antibiotics in antibiotic production wastewater can cause the widespread transmission of antibiotic resistance genes (ARGs). Here, we collected a set of time series samples from a cephalosporin production wastewater treatment plant (X-WWTP), the subsequent municipal WWTP (Y-WWTP) and the receiving stream. Using a functional gene microarray, GeoChip 5.0, which contains multiple homologous probes for 18 ARG and 13 antibiotic metabolism gene (AMG) families, we found that more than 50% of homologous probes for 20 gene families showed a relative abundance higher in X-WWTP, while only 10–20% showed lower relative abundance. The different response patterns of homologous ARG (hARGs) within the same ARG family imply environmental selection pressures are only responsible for the ARG enrichment and spread of some specific instead of all ARG-containing microorganisms, which contradicted the traditionally held belief that environmental selection pressures, especially antibiotic concentration, select for all ARG-containing microorganisms thereby selecting different hARGs in the same ARG family in an undifferentiated way. Network results imply that hARGs from three β_lactamase families enriched under the selection pressure of high cephalosporin antibiotic concentrations in X-WWTP formed positively correlated homologous ARG clusters (pohARGCs). The pohARGCs were also enhanced in the sediment of the receiving stream. The enrichment of hARGs from three β_lactamase families was likely through microorganisms belonging to the Betaproteobacteria genus.

Epichloë occultans infection in Australian Lolium rigidum is associated with cropping history and environment but not with herbicide resistance status of host plant

2018 ◽  
Vol 69 (6) ◽  
pp. 642
Author(s):  
Joseph R. Moore ◽  
James E. Pratley ◽  
Leslie A. Weston ◽  
Wade J. Mace ◽  
John C. Broster ◽  
...  
Keyword(s):  
Herbicide Resistance ◽  
Invasive Plant ◽  
Fungal Endophyte ◽  
Infection Frequency ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Selection Pressures ◽  
Environmental Selection ◽  
Millennium Drought ◽  
Endophyte Infection

Annual ryegrass (Lolium rigidum Gaud.) is a troublesome invasive plant in southern Australian cropping systems and is typically infected with a fungal endophyte, Epichloë occultans. Potential links between herbicide resistance and endophyte infection were investigated in this study. We surveyed 391 ryegrass populations from geographically distinct, naturalised pasture and cropping areas across southern Australia and compared frequencies of seed-borne endophyte infection in the collected seed samples from mature annual ryegrass. Data on herbicide resistance from similar seedlots were cross-referenced with endophyte infection frequency to examine the potential relationship between herbicide resistance and endophyte infection. Seeds from cropping paddocks exhibited a significantly higher frequency of endophyte infection than pasture paddocks sampled from the same region. Frequencies of endophyte infection in annual ryegrass declined across Australia during 2001–09, whereas the opposite trend was observed during 2009–12. Impacts of the Australian Millennium Drought, the correspondingly altered rainfall patterns and environmental selection pressures have a role in determining observed endophyte infection frequencies. However, there was no significant correlation between endophyte frequency and herbicide resistance in the populations evaluated. Differences in endophyte infection frequencies were associated with farming practices, and require further examination to determine causative selection pressures encountered in Australian field settings.

scholarly journals Primate social group sizes exhibit a regular scaling pattern with natural attractors

2018 ◽  
Vol 14 (1) ◽  
pp. 20170490 ◽  
Author(s):  
R. I. M. Dunbar ◽  
Padraig Mac Carron ◽  
Susanne Shultz
Keyword(s):  
Social Networks ◽  
Group Size ◽  
Social Group ◽  
Species Group ◽  
Evolutionary Change ◽  
Selection Pressures ◽  
Environmental Selection ◽  
Rapid Evolutionary Change

Primate groups vary considerably in size across species. Nonetheless, the distribution of mean species group size has a regular scaling pattern with preferred sizes approximating 2.5, 5, 15, 30 and 50 individuals (although strepsirrhines lack the latter two), with a scaling ratio of approximately 2.5 similar to that observed in human social networks. These clusters appear to form distinct social grades that are associated with rapid evolutionary change, presumably in response to intense environmental selection pressures. These findings may have wider implications for other highly social mammal taxa.

Adaptation as genetic internalization

2001 ◽  
Vol 24 (4) ◽  
pp. 673-674
Author(s):  
Adolf Heschl
Keyword(s):  
Living System ◽  
Selection Pressures ◽  
Environmental Selection ◽  
The World ◽  
The Many

In the course of evolution organisms change both their morphology and their physiology in response to ever-changing environmental selection pressures. This process of adaptation leads to an “internalization,” in the sense that external regularities are in some way “imitated” by the living system. Countless examples illustrate the usefulness of this metaphor. However, if we concentrate too much on Shepard's “universal regularities in the world,” we run the risk of overlooking the many more fascinating evolutionary details which alone have made, and still make possible the evolution of diversity on earth. [Shepard]

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