scholarly journals Tracking evolutionary trends towards increasing complexity: a case study in Cyanobacteria

2020 ◽  
Author(s):  
Andrés Moya ◽  
José L. Oliver ◽  
Miguel Verdú ◽  
Luis Delaye ◽  
Vicente Arnau ◽  
...  
Keyword(s):  
Natural Selection ◽  
Genome Evolution ◽  
Biological Function ◽  
Phylogenetic Analyses ◽  
Controversial Issue ◽  
Diverse Group ◽  
Evolutionary Trends ◽  
Genome Complexity ◽  
Environmental Interactions

AbstractProgressive evolution, the tendency towards increasing complexity, is a controversial issue in Biology, whose resolution requires a proper measurement of complexity. Genomes are the best entities to address this challenge, as they record the history and information gaining of organisms in their ongoing biotic and environmental interactions. Using six metrics of genome complexity, none of which is primarily associated to biological function, we measure genome complexity in 91 genomes from the phylum Cyanobacteria. Several phylogenetic analyses reveal the existence of progressive evolution towards higher genome complexity: 1) all the metrics detect strong phylogenetic signals; 2) ridge regressions detect positive trends towards higher complexity; and 3) classical proofs for progressive evolution (the minimum, the ancestor-descendent and the sub-clade tests), show that some of these positive trends are driven, being mainly due to natural selection. These findings support the existence of progressive genome evolution in this ancient and diverse group of organisms.

scholarly journals Driven progressive evolution of genome sequence complexity in Cyanobacteria

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Andrés Moya ◽  
José L. Oliver ◽  
Miguel Verdú ◽  
Luis Delaye ◽  
Vicente Arnau ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Ridge Regression ◽  
Phylogenetic Signal ◽  
Controversial Issue ◽  
Sequence Complexity ◽  
Environmental Interactions ◽  
Genome Level ◽  
Biological Functionality ◽  
Standard Tests

Abstract Progressive evolution, or the tendency towards increasing complexity, is a controversial issue in biology, which resolution entails a proper measurement of complexity. Genomes are the best entities to address this challenge, as they encode the historical information of a species’ biotic and environmental interactions. As a case study, we have measured genome sequence complexity in the ancient phylum Cyanobacteria. To arrive at an appropriate measure of genome sequence complexity, we have chosen metrics that do not decipher biological functionality but that show strong phylogenetic signal. Using a ridge regression of those metrics against root-to-tip distance, we detected positive trends towards higher complexity in three of them. Lastly, we applied three standard tests to detect if progressive evolution is passive or driven—the minimum, ancestor–descendant, and sub-clade tests. These results provide evidence for driven progressive evolution at the genome-level in the phylum Cyanobacteria.

The “Islamization of America”?

2018 ◽  
Author(s):  
Muna Ali
Keyword(s):  
Diverse Group ◽  
Religious Leaders

In addition to the diverse Muslims who invoke the narrative of “pure/true” Islam, there is an unlikely group of non-Muslims Americans who argue that rather than fringe extremist Muslims perverting Islam, it is actually the “pure/true” Islam followers who threaten America and Europe. This alarmist group consists of some conservatives, some political and religious leaders, some new atheist icons, and a cadre of former and current Muslims, many of whom claim to be feminists. This chapter examines the different ideological trends within this diverse group and explores how its members have constructed a narrative of the “Islamization of America.” Through a case study, the chapter demonstrates how this discourse shifted from the margins to the mainstream. It explores whether the rhetoric and actions this narrative inspires is Islamophobia, anti-Muslim racism, or merely a legitimate critique of Muslims and Islam; and the chapter argues that this narrative serves as a strong instrument in the racialization process of Muslims.

scholarly journals Molecular diversity and evolutionary trends of cysteine-rich peptides from the venom glands of Chinese spider Heteropoda venatoria

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jie Luo ◽  
Yiying Ding ◽  
Zhihao Peng ◽  
Kezhi Chen ◽  
Xuewen Zhang ◽  
...  
Keyword(s):  
Expressed Sequence Tags ◽  
Molecular Diversity ◽  
Insect Pests ◽  
Phylogenetic Analyses ◽  
Spider Venom ◽  
Evolutionary Trends ◽  
The Family ◽  
Venom Glands ◽  
Venom Evolution ◽  
Expressed Sequence

AbstractHeteropoda venatoria in the family Sparassidae is highly valued in pantropical countries because the species feed on domestic insect pests. Unlike most other species of Araneomorphae, H. venatoria uses the great speed and strong chelicerae (mouthparts) with toxin glands to capture the insects instead of its web. Therefore, H. venatoria provides unique opportunities for venom evolution research. The venom of H. venatoria was explored by matrix-assisted laser desorption/ionization tandem time-of-flight and analyzing expressed sequence tags. The 154 sequences coding cysteine-rich peptides (CRPs) revealed 24 families based on the phylogenetic analyses of precursors and cysteine frameworks in the putative mature regions. Intriguingly, four kinds of motifs are first described in spider venom. Furthermore, combining the diverse CRPs of H. venatoria with previous spider venom peptidomics data, the structures of precursors and the patterns of cysteine frameworks were analyzed. This work revealed the dynamic evolutionary trends of venom CRPs in H. venatoria: the precursor has evolved an extended mature peptide with more cysteines, and a diminished or even vanished propeptides between the signal and mature peptides; and the CRPs evolved by multiple duplications of an ancestral ICK gene as well as recruitments of non-toxin genes.

Microbial Resistance to Triclosan: A Case Study in Natural Selection

2009 ◽  
Vol 71 (9) ◽  
pp. 536-540
Author(s):  
Amanda Serafini ◽  
Dorothy M. Matthews
Keyword(s):  
Natural Selection ◽  
Microbial Resistance

scholarly journals Revisiting the Scope of Collaboration in the Days of the Great Patriotic War: A Case-Study of the Smolensk Region

2018 ◽  
pp. 856-866
Author(s):  
Dmitriy E. Komarov ◽  
Keyword(s):  
Large Scale ◽  
Local Population ◽  
Controversial Issue ◽  
Potential Threat ◽  
Soviet Government ◽  
Scale Resistance ◽  
Great Patriotic War ◽  
Occupied Territories ◽  
Intense Debate

The article assesses the scope of collaboration in occupied Soviet territories in the days of the Great Patriotic War. This topic is a matter of intense debate in modern Russian scholarship. The most controversial issue is the extent to which Soviet citizens participated in events organized by invaders in occupied territories and the support which local population lent to occupation authorities. The article assesses potential threat of collaborationism in political, as well as economic terms. Having seized the richest and most economically developed regions of the country, the enemy could have significantly strengthened his military potential. National historiography has not yet integrated all data on stratification of local population in their stance toward invaders. It is an extremely difficult task to accomplish nationwide. As occupied territories were culturally, historically and socio-politically heterogeneous, it should be approached by studying republics and regions on a standalone basis. The case-study of the Smolensk region draws on archival materials to determine the share of Soviet citizens cooperating with occupation authorities within the framework of ‘administrative collaboration.’ It concludes that the number of Smolensk families whose members can be classified as ‘administrative collaborators,’ did not exceed 12%, whereas more than 9% of Smolensk families had members who took an active part in the struggle against invaders in the partisan detachments. Thus, the article demonstrates that two extreme irreconcilable phenomena in the occupied territories — collaborationism and partisans movement — were practically in balance. The absolute majority of Smolensk residents (almost 80%) did their utmost to avoid participation in both. Further developments in the Smolensk region proved that their ‘neutrality’ was conditional: the population remained loyal to the Soviet government and formed a social base for large-scale resistance to the occupation policy. Smolensk region became one of the centers of the partisan movement. To a certain extent, Smolensk data can be extrapolated to other western regions of the Russian non-black earth area.

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