Niche segregation and genetic structure of Campylobacter jejuni populations from wild and agricultural host species

AbstractSome symbiont species are highly host-specific, inhabiting only one or a very few host species, and typically have limited dispersal abilities. When they do occur on multiple host species, populations of such symbionts are expected to become genetically structured across these different host species, and this may eventually lead to new symbiont species over evolutionary timescales. However, a low number of dispersal events of symbionts between host species across time might be enough to prevent population structure and species divergence. Overall, processes of evolutionary divergence and the species status of most putative multi-host symbiont systems are yet to be investigated. Here, we used DNA metabarcoding data of 6,023 feather mites (a total of 2,225 OTU representative sequences) from 147 infracommunities (i.e., the assemblage consisting of all mites of different species collected from the same bird host individual) to investigate patterns of population genetic structure and species status of three different putative multi-host feather mite species Proctophyllodes macedo Vitzthum, 1922, Proctophyllodes motacillae Gaud, 1953, and Trouessartia jedliczkai (Zimmerman, 1894), each of which inhabits a variable number of different closely related wagtail host species (genus Motacilla). We show that mite populations from different host species represent a single species. This pattern was found in all the mite species, suggesting that each of these species is a multi-host species in which dispersal of mites among host species prevents species divergence. Also, we found evidence of limited evolutionary divergence manifested by a low but significant level of population genetic structure among symbiont populations inhabiting different host species. Our study agrees with previous studies showing a higher than expected colonization opportunities in host-specific symbionts. Indeed, our results support that these dispersal events would allow the persistence of multi-host species even in symbionts with limited dispersal capabilities, though additional factors such as the geographical structure of some bird populations may also play a role.

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Chickens and Cattle as Sources of Sporadic Domestically Acquired Campylobacter jejuni Infections in Finland

Applied and Environmental Microbiology ◽

10.1128/aem.00374-09 ◽

2009 ◽

Vol 75 (16) ◽

pp. 5244-5249 ◽

Cited By ~ 15

Author(s):

Marjaana Hakkinen ◽

Ulla-Maija Nakari ◽

Anja Siitonen

Keyword(s):

Campylobacter Jejuni ◽

Host Species ◽

Gel Electrophoresis ◽

Pulsed Field Gel Electrophoresis ◽

Farm Animals ◽

Temporal Association ◽

Animal Host ◽

Hygienic Measures ◽

Human Infections

ABSTRACT A substantial sampling among domestic human campylobacter cases, chicken process lots, and cattle at slaughter was performed during the seasonal peak of human infections. Campylobacter jejuni isolates (n = 419) were subtyped using pulsed-field gel electrophoresis with SmaI, and isolates representing overlapping types (n = 212) were further subtyped using KpnI for restriction. The SmaI/KpnI profiles of 55.4% (97/175) of the human isolates were indistinguishable from those of the chicken or cattle isolates. The overlapping SmaI/KpnI subtypes accounted for 69.8% (30/43) and 15.9% (32/201) of the chicken and cattle isolates, respectively. The occurrence of identical SmaI/KpnI subtypes with human C. jejuni isolates was significantly associated with animal host species (P < 0.001). A temporal association of isolates from chickens and patients was possible in 31.4% (55/175) of the human infections. Besides chickens as sources of C. jejuni in the sporadic infections, the role of cattle appears notable. New approaches to restrict the occurrence of campylobacters in other farm animals may be needed in addition to hygienic measures in chicken production. However, only about half of the human infections were attributable to these sources.

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Genetic variation is predominantly structured by geography rather than host in feather mites (Acariformes: Sarcoptiformes) associated with tanagers (Aves: Thraupidae) in Brazil

Entomological Communications ◽

10.37486/2675-1305.ec03044 ◽

2021 ◽

Vol 3 ◽

pp. ec03044

Author(s):

Luiz Gustavo de A. Pedroso ◽

Pavel B. Klimov ◽

Fabio A. Hernandes

Keyword(s):

Genetic Variation ◽

Genetic Structure ◽

Geographic Distribution ◽

Host Species ◽

Intimate Relationship ◽

Genetic Distances ◽

Southern Brazil ◽

Feather Mites ◽

Molecular Barcode ◽

Cox 1

Feather mites are the most common ectosymbionts on birds. These obligatory symbionts are mainly transmitted during their host’s parental care, which creates high host specificity. Due to this intimate relationship, it is thought that their geographic distribution is restricted by their host distribution, or that a host species harbors the same mite composition across its whole range. However, our knowledge regarding the geographic distribution of feather mites remains scarce, with only a few studies indicating disconnections between mite and host distributions, especially in widespread hosts. Here, we investigate the feather mites distribution on four tanager species, three widespread – Thraupis sayaca (L.), T. palmarum (Wied), and Stilpnia cayana (L.) from Northern and Southern Brazil; and the Amazonian T. episcopus (L.). Feather mites were identified using the molecular barcode marker COX-1 using K2P genetic distances. We found a strong genetic structure between Northern and Southern populations of tanagers of more than 10%, even among conspecific hosts. Therefore, the mite distribution on Brazilian tanagers is predominantly shaped by geography rather than by host species. These features in turn reflect historical horizontal transmissions among the hosts, suggesting a high potential for frequent host switches in these symbionts.

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Ecological factors rather than barriers to dispersal shape genetic structure of algal symbionts in horizontally-transmitting corals

10.1101/037994 ◽

2016 ◽

Cited By ~ 4

Author(s):

SW Davies ◽

FC Wham ◽

MR Kanke ◽

MV Matz

Keyword(s):

Genetic Structure ◽

Host Species ◽

Coral Species ◽

Spatial Scales ◽

Horizontal Transmission ◽

Ecological Factors ◽

Local Environment ◽

Transmission Strategy ◽

Algal Symbionts ◽

Genetic Structures

AbstractMany reef-building corals acquire their algal symbionts (Symbiodinium sp.) from the local environment upon recruitment. This horizontal transmission strategy where hosts pair with locally available symbionts could serve to increase coral fitness across diverse environments, as long as hosts maintain high promiscuity and symbionts adapt locally. Here, we tested this hypothesis in two coral species by comparing host and symbiont genetic structures across different spatial scales in Micronesia. Each host species associated with two genetically distinct Symbiodinium lineages, confirming high promiscuity in broadly dispersing hosts. However, contrary to our initial expectation, symbiont genetic structure was independent of physical barriers to dispersal between islands, unlike genetic structure of their hosts that was nearly perfectly explained by ocean currents. Instead, Symbiodinium consistently demonstrated genetic divergence among local reefs and between the two host species at each island, although not necessarily between distant islands. These observations indicate that Symbiodinium lineages disperse much more broadly than previously thought and continuously adapt to specific hosts and reef environments across their range, following the classical Baas Becking’s hypothesis: “Everything is everywhere, but the environment selects”. Overall, our findings confirm that horizontal transmission could be a mechanism for broadly dispersing coral species to enhance their local fitness by associating with locally adapted symbionts. Dramatic differences in factors driving the genetic structures of horizontally-transmitting corals and their Symbiodinium imply that viewing their combined genomes as a single entity (‘hologenome’) would not be useful in the context of their evolution and adaptation.

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Genetic Structure of Magnaporthe grisea Populations Associated with St. Augustinegrass and Tall Fescue in Georgia

Phytopathology ◽

10.1094/phyto-95-0463 ◽

2005 ◽

Vol 95 (5) ◽

pp. 463-471 ◽

Cited By ~ 19

Author(s):

L. P. Tredway ◽

K. L. Stevenson ◽

L. L. Burpee

Keyword(s):

Genetic Structure ◽

Tall Fescue ◽

Host Species ◽

Magnaporthe Grisea ◽

Haplotype Diversity ◽

Diversity Indices ◽

Sample Population ◽

Length Polymorphisms ◽

Amplified Fragment Length Polymorphisms

Amplified fragment length polymorphisms (AFLPs) were used to estimate phylogenetic relationships within Magnaporthe grisea and determine the genetic structure of M. grisea populations associated with tall fescue and St. Augustinegrass in Georgia. Sixteen clonal lineages were identified in a sample population of 948 isolates. Five lineages were isolated from tall fescue (E, G1, G2, G4, and H), with lineage G4 comprising 90% of the population. Isolates from tall fescue were closely related to those from perennial ryegrass, weeping lovegrass, and wheat. Two M. grisea lineages were isolated from St. Augustinegrass (C and K), with lineage C comprising 99.8% of the population. Populations from crabgrass were dominated (98%) by lineage K, but also contained a single lineage C isolate. Haplotype diversity indices ranged from 0.00 to 0.29 in tall fescue populations and from 0.00 to 0.04 in St. Augustinegrass populations. Selection due to host species was the primary factor determining population structure according to analysis of molecular variance; host cultivar and geographical region had no significant effect. The host range of M. grisea lineages from turfgrasses was determined in growth chamber experiments and supports the prominent role of host species in determining the genetic structure of M. grisea populations from turfgrasses in Georgia.

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Differences in host species relationships and biogeographic influences produce contrasting patterns of prevalence, community composition and genetic structure in two genera of avian malaria parasites in southern Melanesia

Journal of Animal Ecology ◽

10.1111/1365-2656.12354 ◽

2015 ◽

Vol 84 (4) ◽

pp. 985-998 ◽

Cited By ~ 34

Author(s):

Sophie Olsson-Pons ◽

Nicholas J. Clark ◽

Farah Ishtiaq ◽

Sonya M. Clegg

Keyword(s):

Genetic Structure ◽

Community Composition ◽

Host Species ◽

Avian Malaria ◽

Species Relationships ◽

Malaria Parasites ◽

Avian Malaria Parasites

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Genetic structure and ecological niche segregation of Indian gray mongoose ( Urva edwardsii ) in Iran

Ecology and Evolution ◽

10.1002/ece3.8168 ◽

2021 ◽

Author(s):

Razie Oboudi ◽

Mansoureh Malekian ◽

Rasoul Khosravi ◽

Davoud Fadakar ◽

Mohammad Ali Adibi

Keyword(s):

Genetic Structure ◽

Ecological Niche ◽

Niche Segregation ◽

Indian Gray Mongoose

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Population genetic structure and phenotypic diversity of Aspidodera raillieti (Nematoda: Heterakoidea), a parasite of Didelphini marsupials in Brazil’s South and Southeast Atlantic Forest

10.21203/rs.3.rs-1192398/v1 ◽

2021 ◽

Author(s):

Karina Varella ◽

Roberto do Val Vilela ◽

Rosana Gentile ◽

Thiago dos Santos Cardoso ◽

Sócrates Fraga da Costa-Neto ◽

...

Keyword(s):

Gene Flow ◽

Genetic Structure ◽

Host Specificity ◽

Atlantic Forest ◽

Host Species ◽

Population Genetic ◽

Fixation Index ◽

The South ◽

Genetic Structuring ◽

Morphometric Variation

Abstract Background: Population genetics of parasites may be influenced by host specificity, life-cycle, geographical distance, evolutionary history, and host-populations structure. The nematode Aspidodera raillieti infects different marsupial and rodent hosts in the Nearctic and Neotropical regions, implying a presumably significant gene flow among populations. However, niche diversification of A. raillieti main hosts in superimposed areas may provide conditions for population genetic structuring within this parasite species. We examined the genetic structuring of A. raillieti infecting three marsupial species co-occurring along South and Southeast Brazilian Atlantic Forest, a hotspot of biodiversity.Methods: We employed morphometric analyses and partial mitochondrial cytochrome c oxidase I gene sequences (MT-CO1) to characterize populations via phylogenetic and phylogeographic analyses.Results: Among 175 A. raillieti specimens recovered from marsupial hosts Didelphis aurita, D. albiventris, and Philander quica, we identified 99 MT-CO1 haplotypes forming four groups in phylogenetic trees and networks. Clades I and II encompassed parasites of D. albiventris from the South region, Clade III comprised parasites of D. aurita from the South and Southeast regions, and Clade IV encompassed parasites of D. aurita and D. albiventris from the South and Southeast regions and parasites of Philander quica from the South region. High genetic differentiation between clades, with a high fixation index and greater genetic variation in the analysis of molecular variance (AMOVA), indicated low gene flow between clades. Haplotypes shared among host species revealed a lack of host specificity. Significant correlation in the Mantel test, suggested parasite isolation by distance, although there was no evidence of geographic structure between populations. Negative values in neutrality tests for Clades III and IV suggested recent population expansion. Morphometric differentiation between A. raillieti specimens recovered from different host species, as well as from different localities, was more evident in males.Conclusion: The genetic structure of A. raillieti populations in the South and Southeast Atlantic Forest resulted from historical events rather than from current geographical distribution or host specificity. We also demonstrate morphometric variation associated with host species and localities, suggesting phenotypic plasticity to host attributes and to spatial variables.

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