scholarly journals Phylogenetics, patterns of genetic variation and population dynamics of Trypanosoma terrestris support both coevolution and ecological host-fitting as processes driving trypanosome evolution

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Sergio D. Pérez ◽  
Jared A. Grummer ◽  
Renata C. Fernandes-Santos ◽  
Caroline Testa José ◽  
Emília Patrícia Medici ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Genetic Variation ◽  
Genetic Structure ◽  
Phylogenetic Analyses ◽  
Host Specialization ◽  
Host Switching ◽  
Ecological Fitting ◽  
The Face ◽  
History Of ◽  
Exclusive Processes

Abstract Background A considerable amount of evidence has favored ecological host-fitting, rather than coevolution, as the main mechanism responsible for trypanosome divergence. Nevertheless, beyond the study of human pathogenic trypanosomes, the genetic basis of host specificity among trypanosomes isolated from forest-inhabiting hosts remains largely unknown. Methods To test possible scenarios on ecological host-fitting and coevolution, we combined a host capture recapture strategy with parasite genetic data and studied the genetic variation, population dynamics and phylogenetic relationships of Trypanosoma terrestris, a recently described trypanosome species isolated from lowland tapirs in the Brazilian Pantanal and Atlantic Forest biomes. Results We made inferences of T. terrestris population structure at three possible sources of genetic variation: geography, tapir hosts and ‘putative’ vectors. We found evidence of a bottleneck affecting the contemporary patterns of parasite genetic structure, resulting in little genetic diversity and no evidence of genetic structure among hosts or biomes. Despite this, a strongly divergent haplotype was recorded at a microgeographical scale in the landscape of Nhecolândia in the Pantanal. However, although tapirs are promoting the dispersion of the parasites through the landscape, neither geographical barriers nor tapir hosts were involved in the isolation of this haplotype. Taken together, these findings suggest that either host-switching promoted by putative vectors or declining tapir population densities are influencing the current parasite population dynamics and genetic structure. Similarly, phylogenetic analyses revealed that T. terrestris is strongly linked to the evolutionary history of its perissodactyl hosts, suggesting a coevolving scenario between Perissodactyla and their trypanosomes. Additionally, T. terrestris and T. grayi are closely related, further indicating that host-switching is a common feature promoting trypanosome evolution. Conclusions This study provides two lines of evidence, both micro- and macroevolutionary, suggesting that both host-switching by ecological fitting and coevolution are two important and non-mutually-exclusive processes driving the evolution of trypanosomes. In line with other parasite systems, our results support that even in the face of host specialization and coevolution, host-switching may be common and is an important determinant of parasite diversification.

Phylogeography and genetic structure of the slow worms Anguis cephallonica and Anguis graeca (Squamata: Anguidae) from the southern Balkan Peninsula

2014 ◽  
Vol 35 (2) ◽  
pp. 263-269 ◽  
Author(s):  
Evanthia Thanou ◽  
Sinos Giokas ◽  
Panagiotis Kornilios
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Genetic Structure ◽  
Genetic Similarity ◽  
Morphological Study ◽  
Phylogenetic Analyses ◽  
Morphological Characteristics ◽  
Balkan Peninsula ◽  
Intraspecific Genetic Diversity ◽  
Well Differentiated

Two slow worm species are distributed at the southernmost part of the Balkan Peninsula: Anguis cephallonica, an endemic of the Peloponnese and the islands Zakynthos, Ithaki and Kephallonia, and A. graeca. Here, we investigate the intraspecific genetic diversity of A. cephallonica from the Peloponnese and Kephallonia and analyse A. graeca, from the northern Peloponnese, where it is found in sympatry with A. cephallonica. MtDNA and nDNA phylogenetic analyses confirm the genetic similarity of Peloponnesian and Kephallonian populations of A. cephallonica and reveal significant mtDNA genetic variation within it, probably related to the occurrence of multiple subrefugia in the Peloponnese. Peloponnesian A. graeca populations are genetically similar to non-Peloponnesian conspecifics implying recent dispersal to the Peloponnese. In contrast to the genetic markers, morphological characteristics (such as the number of mid-body scale-rows) failed to distinguish between Peloponnesian A. cephallonica and A. graeca. Although the former species is believed to be well-differentiated from its congeneric taxa, a thorough morphological study is needed.

scholarly journals Extensive Genetic Diversity of Polyomaviruses in Sympatric Bat Communities: Host Switching versus Coevolution

2020 ◽  
Vol 94 (9) ◽  
Author(s):  
Zhizhou Tan ◽  
Gabriel Gonzalez ◽  
Jinliang Sheng ◽  
Jianmin Wu ◽  
Fuqiang Zhang ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Phylogenetic Analyses ◽  
Mammalian Species ◽  
Host Switching ◽  
Dna Viruses ◽  
Evolutionary Scheme ◽  
History Of ◽  
Murine Polyomavirus ◽  
Horseshoe Bat ◽  
Multiple Species

ABSTRACT Polyomaviruses (PyVs) are small DNA viruses carried by diverse vertebrates. The evolutionary relationships of viruses and hosts remain largely unclear due to very limited surveillance in sympatric communities. In order to investigate whether PyVs can transmit among different mammalian species and to identify host-switching events in the field, we conducted a systematic study of a large collection of bats (n = 1,083) from 29 sympatric communities across China which contained multiple species with frequent contact. PyVs were detected in 21 bat communities, with 192 PyVs identified in 186 bats from 15 species within 6 families representing at least 28 newly described PyVs. Surveillance results and phylogenetic analyses surprisingly revealed three interfamily PyV host-switching events in these sympatric bat communities: two distinct PyVs were identified in two bat species in restricted geographical locations, while another PyV clustered phylogenetically with PyVs carried by bats from a different host family. Virus-host relationships of all discovered PyVs were also evaluated, and no additional host-switching events were found. PyVs were identified in different horseshoe bat species in sympatric communities without observation of host-switching events, showed high genomic identities, and clustered with each other. This suggested that even for PyVs with high genomic identities in closely related host species, the potential for host switching is low. In summary, our findings revealed that PyV host switching in sympatric bat communities can occur but is limited and that host switching of bat-borne PyVs is relatively rare on the predominantly evolutionary background of codivergence with their hosts. IMPORTANCE Since the discovery of murine polyomavirus in the 1950s, polyomaviruses (PyVs) have been considered highly host restricted in mammals. Sympatric bat communities commonly contain several different bat species in an ecological niche facilitating viral transmission, and they therefore represent a model to identify host-switching events of PyVs. In this study, we screened PyVs in a large number of bats in sympatric communities from diverse habitats across China. We provide evidence that cross-species bat-borne PyV transmission exists, though is limited, and that host-switching events appear relatively rare during the evolutionary history of these viruses. PyVs with close genomic identities were also identified in different bat species without host-switching events. Based on these findings, we propose an evolutionary scheme for bat-borne PyVs in which limited host-switching events occur on the background of codivergence and lineage duplication, generating the viral genetic diversity in bats.

scholarly journals High genetic diversity and presence of genetic structure characterise the Corso-Sardinian endemics Ruta corsica and Ruta lamarmorae (Rutaceae)

2018 ◽  
Author(s):  
Marilena Meloni ◽  
Caterina Angela Dettori ◽  
Andrea Reid ◽  
Gianluigi Bacchetta ◽  
Laetitia Hugot ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Biological Diversity ◽  
Taxonomic Status ◽  
Single Species ◽  
Dispersal Ability ◽  
Separate Species ◽  
High Genetic Diversity ◽  
History Of

SummaryCorsica and Sardinia form one of the ten areas with highest biodiversity in the Mediterranean and are considered one of the priority regions for conservation in Europe. In order to preserve the high levels of endemism and biological diversity at different hierarchical levels, knowledge of the evolutionary history and current genetic structure of Corso-Sardinian endemics is instrumental. Microsatellite markers were newly developed and used to study the genetic structure and taxonomic status of Ruta corsica and Ruta lamarmorae, rare endemics of Corsica and Sardinia, respectively, and previously considered a single species. Our analyses identified high levels of genetic variation within each species (P=0.883, He=0.543 for R. corsica; P=0.972, He=0.627 for R. lamarmorae). Intrinsic traits of the species (hermaphroditism, proterandry and polyploidy) and island-dependent factors (i.e. age, origin and history of the islands) might explain the detected high levels of genetic variation. We discovered differentiation between R. corsica and R. lamarmorae, and genetic structure within each species, which are consistent with the observation of low dispersal ability for both species. Our genetic results support the recent taxonomic classification of R. corsica and R. lamarmorae as separate species and suggest that they diverge at only few loci. One R. corsica population (SA) strongly differed from all other studied populations and appeared to be the product of hybridization between the two species in STRUCTURE analyses. Our results provide important insights for the conservation of the two rare endemics. Further genetic analyses are recommended for R. lamarmorae and for population SA (R. corsica).

Unveiling patterns of genetic variation in parasite–host associations: an example with pinworms and Neotropical primates

Parasitology ◽  
2018 ◽  
Vol 146 (3) ◽  
pp. 356-362 ◽  
Author(s):  
Brenda Solórzano García ◽  
Amanda D. Melin ◽  
Filippo Aureli ◽  
Gerardo Pérez Ponce de León
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Central America ◽  
Genetic Divergence ◽  
Evolutionary History ◽  
Phylogenetic Analyses ◽  
Spider Monkey ◽  
Neotropical Primates ◽  
Genetic Patterns ◽  
History Of

AbstractPatterns of genetic variation among populations can reveal the evolutionary history of species. Pinworm parasites are highly host specific and form strong co-evolutionary associations with their primate hosts. Here, we describe the genetic variation observed in four Trypanoxyuris species infecting different howler and spider monkey subspecies in Central America to determine if historical dispersal processes and speciation in the host could explain the genetic patterns observed in the parasites. Mitochondrial (cox1) and ribosomal (28S) DNA were analysed to assess genetic divergence and phylogenetic history of these parasites. Sequences of the 28S gene were identical within pinworms species regardless of host subspecies. However, phylogenetic analyses, haplotype relationships and genetic divergence with cox1 showed differentiation between pinworm populations according to host subspecies in three of the four Trypanoxyuris species analysed. Haplotype separation between host subspecies was not observed in Trypanoxyuris minutus, nor in Trypanoxyuris atelis from Ateles geoffoyi vellerosus and Ateles geoffoyi yucatanensis. Levels of genetic diversity and divergence in these parasites relate with such estimates reported for their hosts. This study shows how genetic patterns uncovered in parasitic organisms can reflect the host phylogenetic and biogeographic histories.

scholarly journals Molecular evolution of the insect-specific flaviviruses

2012 ◽  
Vol 93 (2) ◽  
pp. 223-234 ◽  
Author(s):  
Shelley Cook ◽  
Gregory Moureau ◽  
Andrew Kitchen ◽  
Ernest A. Gould ◽  
Xavier de Lamballerie ◽  
...  
Keyword(s):  
Molecular Evolution ◽  
Phylogenetic Analyses ◽  
Preliminary Evidence ◽  
Future Research ◽  
Host Switching ◽  
Multiple Introductions ◽  
The Family ◽  
Statistical Support ◽  
History Of

There has been an explosion in the discovery of ‘insect-specific’ flaviviruses and/or their related sequences in natural mosquito populations. Herein we review all ‘insect-specific’ flavivirus sequences currently available and conduct phylogenetic analyses of both the ‘insect-specific’ flaviviruses and available sequences of the entire genus Flavivirus. We show that there is no statistical support for virus–mosquito co-divergence, suggesting that the ‘insect-specific’ flaviviruses may have undergone multiple introductions with frequent host switching. We discuss potential implications for the evolution of vectoring within the family Flaviviridae. We also provide preliminary evidence for potential recombination events in the history of cell fusing agent virus. Finally, we consider priorities and guidelines for future research on ‘insect-specific’ flaviviruses, including the vast potential that exists for the study of biodiversity within a range of potential hosts and vectors, and its effect on the emergence and maintenance of the flaviviruses.

Genetic variation within African spiny-tailed lizards (Agamidae: Uromastyx) estimated using mitochondrial DNA sequences

2007 ◽  
Vol 28 (1) ◽  
pp. 1-6 ◽  
Author(s):  
José Brito ◽  
Raquel Vaconcelos ◽  
D. James Harris
Keyword(s):  
Mitochondrial Dna ◽  
Genetic Variation ◽  
Dna Sequences ◽  
Evolutionary History ◽  
Phylogenetic Analyses ◽  
North African ◽  
History Of ◽  
Current Species

AbstractAfrican spiny-tailed lizards (Uromastyx) are large, herbivorous lizards extensively traded locally for food and internationally as pets. Several species have recently been described, although some remain controversial. To determine relationships within North African forms, twenty individuals were analysed for over 1000 bases of mitochondrial DNA sequences. Phylogenetic analyses indicate four deeply divergent lineages that correspond to sampling areas, but not to current species designations. These results indicate that present taxonomy does not reflect the evolutionary history of these species.

scholarly journals Consideration of genetic variation and evolutionary history in future conservation of Indian one-horned rhinoceros (Rhinoceros unicornis)

2022 ◽  
Author(s):  
Tista Ghosh ◽  
Shrewshree Kumar ◽  
Kirtika Sharma ◽  
Parikshit Kakati ◽  
Amit Sharma ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Evolutionary History ◽  
West Bengal ◽  
Indian Subcontinent ◽  
Phylogenetic Analyses ◽  
Population Decline ◽  
Uttar Pradesh ◽  
Anthropogenic Factors ◽  
Rhinoceros Unicornis ◽  
History Of

The extant members of the Eurasian rhino species have experienced severe population and range declines through a combination of natural and anthropogenic factors since the Pleistocene. The one-horned rhino is the only Asian species recovered from such strong population decline but most of their fragmented populations in India and Nepal are reaching carrying capacity. Implementation of any future reintroduction-based conservation efforts would greatly benefit from currently unavailable detailed genetic assessments and the evolutionary history of these populations. We sequenced wild one-horned rhino mitogenomes from all the extant populations (n=16 individuals) for the first time, identified the polymorphic sites and assessed genetic variation (2531bp mtDNA, n=111 individuals) across India. Results showed 30 unique rhino haplotypes distributed as three distinct genetic clades (Fst value 0.68-1) corresponding to the states of Assam (n=28 haplotypes), West Bengal and Uttar Pradesh (both monomorphic). Phylogenetic analyses suggest earlier coalescence of Assam (~0.5 Mya) followed by parallel divergence of West Bengal and Uttar Pradesh/Nepal (~0.06-0.05Mya), supported by the paleobiogeographic history of the Indian subcontinent. Combined together, we propose recognising three Evolutionary Significant Units (ESUs) of the Indian rhino. As recent assessments suggest further genetic isolations of the Indian rhinos at local scales, future management efforts should focus on identifying genetically variable founder animals and consider periodic supplementation events while planning future rhino reintroduction programs in India. Such well-informed, multidisciplinary approach is the only way to ensure evolutionary, ecological and demographic stability of the species across its range.

scholarly journals Genome-wide sequence data show no evidence of admixture and introgression among pollinator wasps associated with a community of Panamanian strangler figs

2020 ◽  
Author(s):  
Jordan D. Satler ◽  
Edward Allen Herre ◽  
Tracy A. Heath ◽  
Carlos A. Machado ◽  
Adalberto Gómez Zúñiga ◽  
...  
Keyword(s):  
Gene Flow ◽  
Evolutionary History ◽  
Phylogenetic Analyses ◽  
Strong Support ◽  
Genetic Admixture ◽  
Host Switching ◽  
Wasp Species ◽  
Pollinator Species ◽  
Genome Wide ◽  
History Of

AbstractInteractions between plants and their animal pollinators can shape processes of divergence and gene flow within associated lineages. For example, in the obligate mutualism between figs (Ficus) and fig pollinator wasps (family Agaonidae), each wasp species typically pollinates a single fig species, potentially reinforcing reproductive isolation among different wasp species. Multiple pollinator species, however, can sometimes reproduce in the same host fig species, potentially enabling hybridization and introgression between wasp species. In a community of Panamanian strangler figs (section Americana), we use genome-wide ultraconserved element (UCE) loci to estimate phylogenetic relationships and test for hybridization and gene flow among 19 pollinator species associated with 16 host fig species. Previous studies showing ongoing pollinator sharing and a history of pollinator host switching are consistent with documented genetic admixture in their host figs. Here we investigate if host sharing and a dynamic evolutionary history including host switching has also resulted in hybridization and gene flow between pollinator species. Phylogenetic analyses recover strong support for well-delimited wasp species coupled with high interspecific divergence. There is no evidence for ongoing hybridization or introgression, even among pairs of pollinator species currently reproducing within the same host. In contrast to work suggesting admixture among Panamanian host figs, we conclude hybridization and interspecific gene flow have not been important processes shaping the evolutionary history of their pollinating wasps.

Luxury Communist Jesus

2016 ◽  
Vol 7 (3) ◽  
pp. 245-255 ◽  
Author(s):  
Michael J. Sandford
Keyword(s):  
Work Ethic ◽  
Protestant Work Ethic ◽  
The Face ◽  
History Of ◽  
The Protestant Work Ethic

This article begins by outlining contemporary anti-work politics, which form the basis of Sandford’s reading. After providing a brief history of anti-work politics, Sandford examines recent scholarly treatments of Jesus’ relationship to work. An examination of a number of texts across the gospel traditions leads Sandford to argue that Jesus can be read as a ‘luxury communist’ whose behaviour flies in the face of the Protestant work ethic. Ultimately, Sandford foregrounds those texts in which Jesus discourages his followers from working, and undermines work as an ‘end in itself’, contextualising these statements in relation to other gospel texts about asceticism and the redistribution of wealth.

Filthy Material

2018 ◽  
Author(s):  
Chris Forster
Keyword(s):  
Twentieth Century ◽  
New Media ◽  
Twentieth Century Literature ◽  
Modernist Literature ◽  
Literary Value ◽  
Radclyffe Hall ◽  
Media Technologies ◽  
The Face ◽  
History Of ◽  
The Media

Modernist literature is inextricable from the history of obscenity. The trials of such figures as James Joyce, D. H. Lawrence, and Radclyffe Hall loom large in accounts of twentieth-century literature. Filthy Material: Modernism and the Media of Obscenity reveals the ways that debates about obscenity and literature were shaped by changes in the history of media. The emergence of film, photography, and new printing technologies shaped how “literary value” was understood, altering how obscenity was defined and which texts were considered obscene. Filthy Material rereads the history of modernist obscenity to discover the role played by technological media in debates about obscenity. The shift from the intense censorship of the early twentieth century to the effective “end of obscenity” for literature at the middle of the century was not simply a product of cultural liberalization but also of a changing media ecology. Filthy Material brings together media theory and archival research to offer a fresh account of modernist obscenity with novel readings of works of modernist literature. It sheds new light on figures at the center of modernism’s obscenity trials (such as Joyce and Lawrence), demonstrates the relevance of the discourse of obscenity to understanding figures not typically associated with obscenity debates (such as T. S. Eliot and Wyndham Lewis), and introduces new figures to our account of modernism (such as Norah James and Jack Kahane). It reveals how modernist obscenity reflected a contest over the literary in the face of new media technologies.

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