scholarly journals Landscape‐scale habitat response of African elephants shows strong selection for foraging opportunities in a human dominated ecosystem

Ecography ◽  
2019 ◽  
Vol 43 (1) ◽  
pp. 149-160 ◽  
Author(s):  
Guillaume Bastille‐Rousseau ◽  
Jake Wall ◽  
Iain Douglas‐Hamilton ◽  
Barnerd Lesowapir ◽  
Benjamin Loloju ◽  
...  
Keyword(s):  
Landscape Scale ◽  
African Elephants ◽  
Strong Selection ◽  
Selection For ◽  
Habitat Response

A note on the voluntary intake of Andropogon gayanus hay by cattle, as affected by level of feeding

1972 ◽  
Vol 15 (1) ◽  
pp. 85-88 ◽  
Author(s):  
G. Zemmelink ◽  
R. J. Haggar ◽  
J. H. Davies
Keyword(s):  
Protein Content ◽  
Feed Intake ◽  
Linear Effect ◽  
Low Level ◽  
Strong Selection ◽  
Andropogon Gayanus ◽  
The Mean ◽  
Voluntary Intake ◽  
Selection For ◽  
White Fulani

SUMMARYUnchaffed Andropogon gayanus hays, harvested in July, September, early-October, late-October and November, and the July to November regrowth, were offered to White Fulani heifers at three levels of feeding.Animals on all hays selected for protein and the mean intake of the different hays was closely related to the protein content of the consumed forage. At the low level of feeding all animals, except those on the July hay, left more than 15% residue. Nevertheless, higher levels of feeding had a marked linear effect on feed intake. This effect was largely independent of the effect of level of feeding on the protein content of the consumed ration and was associated with a strong selection for leaves.

scholarly journals Impact of strong selection for the PrP major gene on genetic variability of four French sheep breeds (Open Access publication)

2008 ◽  
Vol 40 (6) ◽  
pp. 663
Author(s):  
Isabelle Palhiere ◽  
Mickaël Brochard ◽  
Katayoun Moazami-Goudarzi ◽  
Denis Laloë ◽  
Yves Amigues ◽  
...  
Keyword(s):  
Open Access ◽  
Genetic Variability ◽  
Major Gene ◽  
Strong Selection ◽  
Sheep Breeds ◽  
Open Access Publication ◽  
Selection For

Dynamics of Microbial Populations and Strong Selection for Cycloclasticus pugetii following the Nakhodka Oil Spill

2003 ◽  
Vol 46 (4) ◽  
pp. 442-453 ◽  
Author(s):  
A. Maruyama ◽  
H. Ishiwata ◽  
K. Kitamura ◽  
M. Sunamura ◽  
T. Fujita ◽  
...  
Keyword(s):  
Oil Spill ◽  
Microbial Populations ◽  
Strong Selection ◽  
Selection For

scholarly journals New insights on equid locomotor evolution from the lumbar region of fossil horses

2016 ◽  
Vol 283 (1829) ◽  
pp. 20152947 ◽  
Author(s):  
Katrina Elizabeth Jones
Keyword(s):  
Body Size ◽  
Adaptive Evolution ◽  
Axial Skeleton ◽  
Lumbar Region ◽  
Scaling Effects ◽  
Classic Case ◽  
Strong Selection ◽  
Selection For ◽  
Joint Shape

The specialization of equid limbs for cursoriality is a classic case of adaptive evolution, but the role of the axial skeleton in this famous transition is not well understood. Extant horses are extremely fast and efficient runners, which use a stiff-backed gallop with reduced bending of the lumbar region relative to other mammals. This study tests the hypothesis that stiff-backed running in horses evolved in response to evolutionary increases in body size by examining lumbar joint shape from a broad sample of fossil equids in a phylogenetic context. Lumbar joint shape scaling suggests that stability of the lumbar region does correlate with size through equid evolution. However, scaling effects were dampened in the posterior lumbar region, near the sacrum, which suggests strong selection for sagittal mobility in association with locomotor–respiratory coupling near the lumbosacral joint. I hypothesize that small-bodied fossil horses may have used a speed-dependent running gait, switching between stiff-backed and flex-backed galloping as speed increased.

scholarly journals Barley β-amylase and β-glucanase activities at germination in vulgare-type lines from backcrosses of wild, spontaneum strains with cv. Adorra

1992 ◽  
Vol 1 (3) ◽  
pp. 339-350
Author(s):  
Hannu Ahokas ◽  
Maria J. Erkkilä
Keyword(s):  
High Activity ◽  
Soluble Protein ◽  
Amylase Activity ◽  
Hordeum Spontaneum ◽  
Recurrent Parent ◽  
Glucanase Activity ◽  
Strong Selection ◽  
Selection For ◽  
Aseptic Conditions ◽  
Derivation Process

Two hundred and nineteen lines derived from the backcross progenies of eight different Hordeum spontaneum strains were evaluated for β-amylase and β-glucanase activity five days after germination under aseptic conditions. The activities were determined on the basis of soluble protein or grain mass. The recurrent parent cultivar, Adorra, served as the standard. Putative recombinants with high B-amylase activity were relatively easily achieved from high-activity strains of H. spontaneum. Recombinants with high β-glucanase were rare. They appear to be eliminated, possibly due to the strong selection for the domesticated phenotype during the derivation process.

scholarly journals Strong selection for behavioural resilience in Australian stock working dogs identified by selective sweep analysis

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Elizabeth R Arnott ◽  
Lincoln Peek ◽  
Jonathan B Early ◽  
Annie Y H Pan ◽  
Bianca Haase ◽  
...  
Keyword(s):  
Selective Sweep ◽  
Strong Selection ◽  
Working Dogs ◽  
Selection For

scholarly journals Estimating the strength of selection for new SARS-CoV-2 variants

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Christiaan H. van Dorp ◽  
Emma E. Goldberg ◽  
Nick Hengartner ◽  
Ruian Ke ◽  
Ethan O. Romero-Severson
Keyword(s):  
Molecular Epidemiology ◽  
Selective Advantage ◽  
Global Perspective ◽  
Detailed Model ◽  
Strong Selection ◽  
Time Horizons ◽  
New Variant ◽  
Selection For ◽  
Global Threat ◽  
Substantial Heterogeneity

AbstractControlling the SARS-CoV-2 pandemic becomes increasingly challenging as the virus adapts to human hosts through the continual emergence of more transmissible variants. Simply observing that a variant is increasing in frequency is relatively straightforward, but more sophisticated methodology is needed to determine whether a new variant is a global threat and the magnitude of its selective advantage. We present two models for quantifying the strength of selection for new and emerging variants of SARS-CoV-2 relative to the background of contemporaneous variants. These methods range from a detailed model of dynamics within one country to a broad analysis across all countries, and they include alternative explanations such as migration and drift. We find evidence for strong selection favoring the D614G spike mutation and B.1.1.7 (Alpha), weaker selection favoring B.1.351 (Beta), and no advantage of R.1 after it spreads beyond Japan. Cutting back data to earlier time horizons reveals that uncertainty is large very soon after emergence, but that estimates of selection stabilize after several weeks. Our results also show substantial heterogeneity among countries, demonstrating the need for a truly global perspective on the molecular epidemiology of SARS-CoV-2.

scholarly journals More Evidence of Collusion: a New Prophage-Mediated Viral Defense System Encoded by Mycobacteriophage Sbash

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Gabrielle M. Gentile ◽  
Katherine S. Wetzel ◽  
Rebekah M. Dedrick ◽  
Matthew T. Montgomery ◽  
Rebecca A. Garlena ◽  
...  
Keyword(s):  
Microbial Evolution ◽  
Bacterial Survival ◽  
Defense System ◽  
Microbial World ◽  
Content Type ◽  
Strong Selection ◽  
Defense Systems ◽  
Expression Of Genes ◽  
Bacterial Chromosomes ◽  
Selection For

ABSTRACTThe arms race between bacteria and their bacteriophages profoundly influences microbial evolution. With an estimated 1023phage infections occurring per second, there is strong selection for both bacterial survival and phage coevolution for continued propagation. Many phage resistance systems, including restriction-modification systems, clustered regularly interspaced short palindromic repeat-Cas (CRISPR-Cas) systems, a variety of abortive infection systems, and many others that are not yet mechanistically defined, have been described. Temperate bacteriophages are common and form stable lysogens that are immune to superinfection by the same or closely related phages. However, temperate phages collude with their hosts to confer defense against genomically distinct phages, to the mutual benefit of the bacterial host and the prophage. Prophage-mediated viral systems have been described inMycobacteriumphages andPseudomonasphages but are predicted to be widespread throughout the microbial world. Here we describe a new viral defense system in which the mycobacteriophage Sbash prophage colludes with itsMycobacterium smegmatishost to confer highly specific defense against infection by the unrelated mycobacteriophage Crossroads. Sbash genes30and31are lysogenically expressed and are necessary and sufficient to confer defense against Crossroads but do not defend against any of the closely related phages grouped in subcluster L2. The mapping of Crossroads defense escape mutants shows that genes132and141are involved in recognition by the Sbash defense system and are proposed to activate a loss in membrane potential mediated by Sbash gp30 and gp31.IMPORTANCEViral infection is an ongoing challenge to bacterial survival, and there is strong selection for development or acquisition of defense systems that promote survival when bacteria are attacked by bacteriophages. Temperate phages play central roles in these dynamics through lysogenic expression of genes that defend against phage attack, including those unrelated to the prophage. Few prophage-mediated viral defense systems have been characterized, but they are likely widespread both in phage genomes and in the prophages integrated in bacterial chromosomes.

scholarly journals Nonlinear acoustic complexity in a fish ‘two-voice’ system

2011 ◽  
Vol 278 (1725) ◽  
pp. 3762-3768 ◽  
Author(s):  
Aaron N. Rice ◽  
Bruce R. Land ◽  
Andrew H. Bass
Keyword(s):  
Social Communication ◽  
Selection Pressure ◽  
Motor System ◽  
Sound Production ◽  
Nonlinear Characteristics ◽  
Strong Selection ◽  
Vocal Signals ◽  
Nonlinear Acoustic ◽  
Selection For ◽  
Mathematical Analyses

Acoustic signals play essential roles in social communication and show a strong selection for novel morphologies leading to increased call complexity in many taxa. Among vertebrates, repeated innovations in the larynges of frogs and mammals and the syrinx of songbirds have enhanced the spectro-temporal content, and hence the diversity of vocalizations. This acoustic diversification includes nonlinear characteristics that expand frequency profiles beyond the traditional categorization of harmonic and broadband calls. Fishes have remained a notable exception to evidence for such acoustic innovations among vertebrates, despite their being the largest group of living vertebrates that also exhibit widespread evolution of sound production. Here, we combine rigorous acoustic and mathematical analyses with experimental silencing of the vocal motor system to show how a novel swim bladder mechanism in a toadfish enables it to generate calls exhibiting nonlinearities like those found among frogs, birds and mammals, including primates. By showing that fishes have evolved nonlinear acoustic signalling like all other major lineages of vocal vertebrates, these results suggest strong selection pressure favouring this mechanism to enrich the spectro-temporal content and complexity of vocal signals.

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