scholarly journals Plant speciation in the Namib Desert: origin of a widespread derivative species from a narrow endemic

2022 ◽  
Author(s):  
Joseph J Milton ◽  
Matthias Affenzeller ◽  
Richard J Abbott ◽  
Hans-Peter Comes
Keyword(s):  
Single Gene ◽  
Distinct Species ◽  
Plant Evolution ◽  
Dispersal Ability ◽  
North African ◽  
Namib Desert ◽  
Hybrid Incompatibility ◽  
Niche Divergence ◽  
Northward Expansion

Background: Parapatric (or budding) speciation is increasingly recognized as an important phenomenon in plant evolution but its role in extreme (e.g. desert) environments is poorly documented. Aims: To test this speciation model in a hypothesized sister pair, the Southwest and North African disjunct Senecio flavus and its putative progenitor, the Namibian Desert endemic S. englerianus. Methods: Phylogenetic inferences were combined with niche divergence tests, morphometrics, and experimental genetic approaches. We also evaluated the potential role of an African Dry Corridor (ADC) in promoting the hypothesized northward expansion of S. flavus (from Namibia), using palaeodistribution models. Results: Belonging to an isolated (potentially relict) clade, the two morphologically distinct species show pronounced niche divergence in Namibia and signs of digenic epistatic hybrid incompatibility (based on F2 pollen fertility). The presence of connate fluked pappus hairs in S. flavus, likely increasing dispersal ability, is controlled by a single gene locus. Conclusions: Our results provide support for a rare example of budding speciation in which a wider ranged derivative (S. flavus) originated at the periphery of a smaller ranged progenitor (S. englerianus) in the Namib Desert region. The Southwest and North African disjunction of S. flavus could have been established by dispersal across intermediate ADC areas during periods of (Late) Pleistocene aridification.

scholarly journals Influence of Land Use on Avian Diversity in North African Urban Environments

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 434
Author(s):  
Hani Amir Aouissi ◽  
Alexandru-Ionuţ Petrişor ◽  
Mostefa Ababsa ◽  
Maria Boştenaru-Dan ◽  
Mahmoud Tourki ◽  
...  
Keyword(s):  
Green Infrastructure ◽  
Diversity Index ◽  
Research Question ◽  
Urban Environments ◽  
Ecological Group ◽  
Avian Diversity ◽  
North African ◽  
Index Method ◽  
Urban Green Spaces

Land cover and use changes are important to study for their impact on ecosystem services and ultimately on sustainability. In urban environments, a particularly important research question addresses the relationship between urbanization-related changes and biodiversity, subject to controversies in the literature. Birds are an important ecological group, and useful for answering this question. The present study builds upon the hypothesis according to which avian diversity decreases with urbanization. In order to answer it, a sample of 4245 observations from 650 sites in Annaba, Algeria, obtained through the point abundance index method, were investigated by computing Shannon-Wiener’s diversity index and the species richness, mapping them, and analyzing the results statistically. The findings confirm the study hypothesis and are relevant for planning, as they stress the role of urban green spaces as biodiversity hotspots, and plead for the need of connecting them. From a planning perspective, the results emphasize the need for interconnecting the green infrastructure through avian corridors. Moreover, the results fill in an important lack of data on the biodiversity of the region, and are relevant for other similar Mediterranean areas. Future studies could use the findings to compare with data from other countries and continents.

The Ideological Dimensionality in the Middle Eastern and North African Constitutions: A New Era in the Evolution of Islamic Constitutionalism

2020 ◽  
pp. 147892992091294
Author(s):  
Berna Öney
Keyword(s):  
Middle Eastern ◽  
Political Regime ◽  
North African ◽  
New Era ◽  
Regime Changes ◽  
Political Debates ◽  
Before And After ◽  
Popular Movements ◽  
Ideological Dimension

The popular movements in 2011 led to many regime changes that resulted in amended or new constitutions in the Middle East and North Africa region. The constitutional debates concentrated mainly on the functions of the constitutions in authoritarian regimes, constitution-making processes, and the role of Islam during and after the uprisings. However, no research has analyzed the ideological dimensionality of the Middle Eastern and North African constitutions. By analyzing 19 newly enacted, drafted, and amended constitutions before and after the popular movements in the region, this article shows that the single ideological dimension in the constitutions can be defined by the openness of a state for liberal and modern values. This ideological dimension encompasses all the regional political debates on the political regime dynamics, the inclusion of rights and liberties, and the role of Islam. Besides offering an alternative typology for the constitutions in the region, this article also provides evidence for the beginning of the fourth phase of Islamic constitutionalism that merges the ideas of rule of law, which originates from democratic notions, and Islamic norms.

An unexpected new record of the Mediterranean orchid, Ophrys bertolonii (Orchidaceae) in Central Europe

Biologia ◽  
2011 ◽  
Vol 66 (5) ◽  
Author(s):  
Attila Molnár V ◽  
András Máté ◽  
Gábor Sramkó
Keyword(s):  
Central Europe ◽  
New Record ◽  
Dispersal Ability ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Permanent Establishment ◽  
Adriatic Coast ◽  
Northward Expansion ◽  
Mediterranean Plant

AbstractOne flowering specimen of Ophrys bertolonii (s. str.) — a plant with a Circum-Adriatic distribution and hitherto unknown in other regions — was found on 7th May 2010 in the vicinity of Kunadacs (Central Hungary; N 47°00′ E 19°17′). The nearest known populations of this Mediterranean plant inhabit the Adriatic coast (ca. 450 km away) in Croatia, therefore this new occurrence represents a significant long distance dispersal event. The circumstances of the occurrence argue against introduction, but we can not decide now whether this new appearance is temporary or permanent. The permanent establishment of this strictly entomophilous plant requires the presence of its specific pollinator in the close neighbourhood of the habitat. However, no pollination was observed on the three flowers of the plant until 9th May, and one day later the stem had disappeared most likely due to grazing. Whatever the long-term fate of the plant is, this discovery represents a significant long distance (jump) dispersal event, and testifies to the dispersal ability of Ophrys species. Additionally, the appearance of a mature Adriatic plant in Central Europe fits well into the currently observed, climate change driven northward expansion of European orchids, therefore this finding most likely reflects a growing Mediterranean-like climatic influence in the region.

Reaching Future Scientists, Consumers, & Citizens

2014 ◽  
Vol 76 (6) ◽  
pp. 379-383 ◽  
Author(s):  
Melissa A. Hicks ◽  
Rebecca J. Cline ◽  
Angela M. Trepanier
Keyword(s):  
Personalized Medicine ◽  
Genetic Basis ◽  
Genetic Disorders ◽  
Single Gene ◽  
Personal Health ◽  
Adult Onset ◽  
Biology Textbooks ◽  
Multifactorial Diseases ◽  
Single Gene Disorders

An understanding of how genomics information, including information about risk for common, multifactorial disease, can be used to promote personal health (personalized medicine) is becoming increasingly important for the American public. We undertook a quantitative content analysis of commonly used high school textbooks to assess how frequently the genetic basis of common multifactorial diseases was discussed compared with the “classic” chromosomal–single gene disorders historically used to teach the concepts of genetics and heredity. We also analyzed the types of conditions or traits that were discussed. We identified 3957 sentences across 11 textbooks that addressed multifactorial and “classic” genetic disorders. “Classic” gene disorders were discussed relatively more frequently than multifactorial diseases, as was their genetic basis, even after we enriched the sample to include five adult-onset conditions common in the general population. Discussions of the genetic or hereditary components of multifactorial diseases were limited, as were discussions of the environmental components of these conditions. Adult-onset multifactorial diseases are far more common in the population than chromosomal or single-gene disorders; many are potentially preventable or modifiable. As such, they are targets for personalized medical approaches. The limited discussion in biology textbooks of the genetic basis of multifactorial conditions and the role of environment in modifying genetic risk may limit the public’s understanding and use of personalized medicine.

scholarly journals Study of Staphylococcus aureusPathogenic Genes by Transfer and Expression in the Less Virulent Organism Streptococcus gordonii

2001 ◽  
Vol 69 (2) ◽  
pp. 657-664 ◽  
Author(s):  
P. Stutzmann Meier ◽  
J. M. Entenza ◽  
P. Vaudaux ◽  
P. Francioli ◽  
M. P. Glauser ◽  
...  
Keyword(s):  
Single Gene ◽  
Individual Factors ◽  
Gene Products ◽  
Streptococcus Gordonii ◽  
Pathogenic Role ◽  
Gain Of Function ◽  
Function Strategy

ABSTRACT Because Staphylococcus aureus strains contain multiple virulence factors, studying their pathogenic role by single-gene inactivation generated equivocal results. To circumvent this problem, we have expressed specific S. aureus genes in the less virulent organism Streptococcus gordonii and tested the recombinants for a gain of function both in vitro and in vivo. Clumping factor A (ClfA) and coagulase were investigated. Both gene products were expressed functionally and with similar kinetics during growth by streptococci and staphylococci. ClfA-positive S. gordoniiwas more adherent to platelet-fibrin clots mimicking cardiac vegetations in vitro and more infective in rats with experimental endocarditis (P < 0.05). Moreover, deletingclfA from clfA-positive streptococcal transformants restored both the low in vitro adherence and the low in vivo infectivity of the parent. Coagulase-positive transformants, on the other hand, were neither more adherent nor more infective than the parent. Furthermore, coagulase did not increase the pathogenicity ofclfA-positive streptococci when both clfA andcoa genes were simultaneously expressed in an artificial minioperon in streptococci. These results definitively attribute a role for ClfA, but not coagulase, in S. aureus endovascular infections. This gain-of-function strategy might help solve the role of individual factors in the complex the S. aureus-host relationship.

scholarly journals Mediterranean Heathland as a Key Habitat for Fire Adaptations: Evidence from an Experimental Approach

Forests ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 748
Author(s):  
Susana Gómez-González ◽  
Maria Paniw ◽  
Mario Durán ◽  
Sergio Picó ◽  
Irene Martín-Rodríguez ◽  
...  
Keyword(s):  
Heat Shock ◽  
Seed Size ◽  
Mediterranean Basin ◽  
Fire Ecology ◽  
Mediterranean Region ◽  
Plant Evolution ◽  
Fire Adaptations ◽  
The Mediterranean ◽  
The Mediterranean Basin

Some fire ecology studies that have focused on garrigue-like vegetation suggest a weak selective pressure of fire in the Mediterranean Basin compared to other Mediterranean-type regions. However, fire-prone Mediterranean heathland from the western end of the Mediterranean Basin has been frequently ignored in the fire ecology literature despite its high proportion of pyrogenic species. Here, we explore the evolutionary ecology of seed traits in the generalist rockrose Cistus salviifolius L. (Cistaceae) aiming to ascertain the role of the Mediterranean heathland for fire adaptations in the Mediterranean Region. We performed a germination experiment to compare the relationship of seed size to (i) heat-stimulated germination, (ii) dormancy strength, and (iii) heat survival in plants from ‘high-fire’ heathland vs. ‘low-fire’ coastal shrubland. Germination after heat-shock treatment was higher in large seeds of both ‘high-fire’ and ‘low-fire’ habitats. However, dormancy was weaker in small seeds from ‘low-fire’ habitats. Finally, seed survival to heat shock was positively related to seed size. Our results support that seed size is an adaptive trait to fire in C. salviifolius, since larger seeds had stronger dormancy, higher heat-stimulated germination and were more resistant to heat shock. This seed size–fire relationship was tighter in ‘high-fire’ Mediterranean heathland than ‘low-fire’ coastal shrubland, indicating the existence of differential fire pressures and evolutionary trends at the landscape scale. These findings highlight the Mediterranean heathland as a relevant habitat for fire-driven evolution, thus contributing to better understand the role of fire in plant evolution within the Mediterranean region.

scholarly journals The role of dispersal for shaping phylogeographical structure of flightless beetles from the Andes

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7226 ◽  
Author(s):  
Sofia I. Muñoz-Tobar ◽  
Michael S. Caterino
Keyword(s):  
Mitochondrial Gene ◽  
Ground Beetle ◽  
Population Level ◽  
Population Subdivision ◽  
Dispersal Ability ◽  
Population Isolation ◽  
Small Areas ◽  
Maximum Entropy Models ◽  
The Andes

Background Páramo is a tropical alpine ecosystem present in the northern Andes. Its patchy distribution imposes limits and barriers to specialist inhabitants. We aim to assess the effects of this habitat distribution on divergence across two independently flightless ground beetle lineages, in the genera Dyscolus and Dercylus. Methods One nuclear and one mitochondrial gene from 110 individuals from 10 sites across the two lineages were sequenced and analyzed using a combination of phylogenetics, population genetic analyses, and niche modeling methods. Results The two lineages show different degrees of population subdivision. Low levels of gene flow were found in Dyscolus alpinus, where one dominant haplotype is found in four out of the six populations analyzed for both molecular markers. However, complete population isolation was revealed in species of the genus Dercylus, where high levels of differentiation exist at species and population level for both genes. Maximum entropy models of species in the Dercylus lineage show overlapping distributions. Still, species distributions appear to be restricted to small areas across the Andes. Conclusion Even though both beetle lineages are flightless, the dispersal ability of each beetle lineage appears to influence the genetic diversity across fragmented páramo populations, where Dyscolus alpinus appears to be a better disperser than species in the genus Dercylus.

The local and global in North African popular music

Popular Music ◽  
1996 ◽  
Vol 15 (3) ◽  
pp. 259-273 ◽  
Author(s):  
Tony Langlois
Keyword(s):  
Popular Music ◽  
Political Party ◽  
North African ◽  
Islamic Movement ◽  
Public Figures ◽  
The World ◽  
East And West ◽  
Victims Of Violence ◽  
The City

On 29 September 1994, Cheb Hasni, the most renowned Rai singer living in Algeria, was gunned down outside his family's house in Gambetta, a quarter of the city of Waharan (Oran). He was one of many public figures (and some 50,000 others) who have been killed since the main opposition political party, the FIS (Islamic Salvation Front) was prevented from assuming power by the annulment of elections that they would have won in 1991. Like the most notable of Algeria's victims of violence, which include journalists, lawyers, doctors, television presenters and top policemen, Hasni represented a version of Algerian identity that some people clearly could not tolerate. Responsibility for his assassination has not been claimed, but the manner of his death was identical to others carried out by the armed faction of the fundamentalist Islamic movement, the GIA (Armed Islamic Group). His death has possibly marked the demise of a genre of North African popular music known as Rai as it was produced in Algeria. Rai has been a particularly problematic idiom for Islamists and secularists alike. Both groups nurture distinct views of the place of Algeria, and Algerians in the world, and the role of Islam and liberal secularism in Algeria. Rai music constructs its own distinct trajectories linking local and global, ‘East’ and ‘West’, and, in this way, constitutes a distinct problem for Algerians, and indeed other North Africans today.

Genes necessary for C. elegans cell and growth cone migrations

Development ◽  
1997 ◽  
Vol 124 (9) ◽  
pp. 1831-1843 ◽  
Author(s):  
W.C. Forrester ◽  
G. Garriga
Keyword(s):  
Cell Fate ◽  
Single Gene ◽  
Growth Cones ◽  
Cell Fate Specification ◽  
Fate Specification ◽  
C Elegans ◽  
Final Destination ◽  
Multiple Cell

The migrations of cells and growth cones contribute to form and pattern during metazoan development. To study the mechanisms that regulate cell motility, we have screened for C. elegans mutants defective in the posteriorly directed migrations of the canal-associated neurons (CANs). Here we describe 14 genes necessary for CAN cell migration. Our characterization of the mutants has led to three conclusions. First, the mutations define three gene classes: genes necessary for cell fate specification, genes necessary for multiple cell migrations and a single gene necessary for final positioning of migrating cells. Second, cell interactions between the CAN and HSN, a neuron that migrates anteriorly to a position adjacent to the CAN, control the final destination of the HSN cell body. Third, C. elegans larval development requires the CANs. In the absence of CAN function, larvae arrest development, with excess fluid accumulating in their pseudocoeloms. This phenotype may reflect a role of the CANs in osmoregulation.

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