scholarly journals Uneven distribution of cryptic diversity among higher taxa of parasitic worms

2010 ◽  
Vol 7 (2) ◽  
pp. 241-244 ◽  
Author(s):  
Robert Poulin
Keyword(s):  
Cryptic Species ◽  
Zoonotic Diseases ◽  
Helminth Parasites ◽  
Morphological Markers ◽  
Molecular Tools ◽  
Invasive Pathogens ◽  
Higher Taxa ◽  
As Species ◽  
Species Specific ◽  
Parasitic Worms

Cryptic species cause problems for estimates of biodiversity. In the case of parasites, cryptic species also plague efforts to detect potential zoonotic diseases or invasive pathogens. It is crucial to determine whether the likelihood of finding cryptic species differs among higher parasite taxa, to better calibrate estimates of diversity and monitor diseases. Using published reports of cryptic species of helminth parasites identified using molecular tools, I show that the number of species found is strongly related to the number of parasite individuals sequenced, weakly influenced by the number of host species from which parasites were obtained, and unaffected by the genetic markers used. After correction for these factors, more cryptic species of trematodes are found than in other helminth taxa. Although several features distinguish trematodes from other helminths, it is probable that our inability to discriminate among sibling species of trematodes results from their lack of structures serving as species-specific morphological markers. The available data suggest that current estimates of helminth diversity may need to be doubled (tripled for trematodes) to better reflect extant diversity.

scholarly journals Are members of the Anopheles fluviatilis complex conspecific?

2021 ◽  
Author(s):  
Om P Singh ◽  
Ankita Sindhania ◽  
Gunjan Sharma ◽  
Shobhna Mishra ◽  
Surya K Sharma ◽  
...  
Keyword(s):  
Cryptic Species ◽  
Specific Primer ◽  
Pcr Assay ◽  
Sympatric Populations ◽  
Diagnostic Pcr ◽  
Specific Pcr ◽  
Anopheles Fluviatilis ◽  
As Species ◽  
Specific Pcr Assay ◽  
Species Specific

Anopheles fluviatilis sensu lato, a primary malaria vector in India, was identified to be comprised of four cryptic species, provisionally designated as species S, T, U and V. However, Kumar et al. (Mol Ecol Resour, 2013;13:354-61) considered all of the then known three members of this species complex (S, T and U) conspecific. The specific status of species S and T was refuted based on the lack of sufficient barcode gap in mitochondrial-CO1 and the perceived presence of heterozygotes in populations as detected through one of the two species-specific PCR assays employed for the cryptic species identification. The existence of species U was refuted claiming that earlier investigations have already refuted their existence. This conclusion is concerning because of the differential public health implications of members of the Fluviatilis Complex. Here we discuss problems associated with the CO1-based barcode approach for delimitation of cryptic species, the perceived heterozygosity between species S and T based on a species-specific PCR assay, and interpretation of published reports. We demonstrated that fixed differences do exist in the ITS2-rDNA sequence of species S and T with no evidence of heterozygotes in sympatric populations and, that the observed heterozygosity by Kumar et al. in the ITS2-based species diagnostic PCR is due to the high mispriming tendency of the T-specific primer with species S. We infer that mitochondrial DNA-based barcoding-gap, an arbitrary threshold recommended for species delimitation, alone, is inadequate to delimit the members of An. fluviatilis complex.

scholarly journals Flight-call as species-specific signal in South American parrots and the effect of species relatedness in call similarity

2017 ◽  
Vol 25 (3) ◽  
pp. 143-151 ◽  
Author(s):  
Carlos B. de Araújo ◽  
Paulo A. M. Marques ◽  
Jacques M. E. Vielliard
Keyword(s):  
South American ◽  
Specific Signal ◽  
As Species ◽  
Species Specific

Explaining variability in parasite aggregation levels among host samples

Parasitology ◽  
2013 ◽  
Vol 140 (4) ◽  
pp. 541-546 ◽  
Author(s):  
ROBERT POULIN
Keyword(s):  
Body Size ◽  
Strong Relationship ◽  
Host Susceptibility ◽  
Helminth Parasites ◽  
Susceptibility To Infection ◽  
Host Body ◽  
Parasite Aggregation ◽  
Using Data ◽  
Species Specific ◽  
Host Body Size

SUMMARYAggregated distributions among individual hosts are a defining feature of metazoan parasite populations. Heterogeneity among host individuals in exposure to parasites or in susceptibility to infection is thought to be the main factor generating aggregation, with properties of parasites themselves explaining some of the variability in aggregation levels observed among species. Here, using data from 410 samples of helminth parasites on fish hosts, I tested the contribution of (i) within-sample variation in host body size, taken as a proxy for variability in host susceptibility, and (ii) parasite taxon and developmental stage, to the aggregated distribution of parasites. Log-transformed variance in numbers of parasites per host was regressed against log mean number across all samples; the strong relationship (r2 = 0·88) indicated that aggregation levels are tightly constrained by mean infection levels, and that only a small proportion of the observed variability in parasite aggregation levels remains to be accounted for by other factors. Using the residuals of this regression as measures of ‘unexplained’ aggregation, a mixed effects model revealed no significant effect of within-sample variation in host body size or of parasite taxon or stage (i.e. juvenile versus adult) on parasite aggregation level within a sample. However, much of the remaining variability in parasite aggregation levels among samples was accounted for by the number of individual hosts examined per sample, and species-specific and study-specific effects reflecting idiosyncrasies of particular systems. This suggests that with most differences in aggregation among samples already explained, there may be little point in seeking universal causes for the remaining variation.

scholarly journals Trichothecene Genotypes of Fusarium graminearum Populations Isolated from Winter Wheat Crops in Serbia

Toxins ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 460 ◽  
Author(s):  
Vesna Krnjaja ◽  
Slavica Stanković ◽  
Ana Obradović ◽  
Tanja Petrović ◽  
Violeta Mandić ◽  
...  
Keyword(s):  
Fusarium Graminearum ◽  
Gene Clusters ◽  
Sensu Stricto ◽  
Molecular Techniques ◽  
Weather Data ◽  
Morphological Observation ◽  
Specific Primer ◽  
Head Blight ◽  
As Species ◽  
Species Specific

Fusarium graminearum as the main causal agent of Fusarium head blight (FHB) and its ability to produce trichothecenes was investigated by molecular techniques. A total of 37 strains isolated from the wheat, harvested in Serbia in 2005, 2008 and 2015, and previously designated by morphological observation as F. graminearum, were used for trichothecene genotypes characterization. The strains were identified using the species-specific primer set FG16R/FG16F while genotypic characterization was done using specific TRI13 and TRI3 sequences of the trichothecene gene clusters. The PCR assays identified all strains as species of F. graminearum sensu stricto with the DON/15-ADON genotype. The quantification of the mycotoxin (DON) was performed using the biochemical assay. The high levels of DON (>20,000 µg kg−1) were recorded in all of the strains from 2005, four strains from 2008 and two strains from 2015. Weather data of the investigated seasons, showed that the optimal temperature, frequent rains and high relative humidity (RH) was very favourable for the development of F. graminearum, affecting the DON biosynthesis.

scholarly journals Green Fluorescence Patterns in Closely Related Symbiotic Species of Zanclea (Hydrozoa, Capitata)

Diversity ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 78 ◽  
Author(s):  
Davide Maggioni ◽  
Luca Saponari ◽  
Davide Seveso ◽  
Paolo Galli ◽  
Andrea Schiavo ◽  
...  
Keyword(s):  
Cryptic Species ◽  
Genetic Divergence ◽  
Large Scale ◽  
Marine Invertebrates ◽  
Fluorescent Proteins ◽  
Green Fluorescent Proteins ◽  
Green Fluorescence ◽  
Promising Tool ◽  
Species Specific ◽  
Green Fluorescent

Green fluorescence is a common phenomenon in marine invertebrates and is caused by green fluorescent proteins. Many hydrozoan species display fluorescence in their polyps and/or medusa stages, and in a few cases patterns of green fluorescence have been demonstrated to differ between closely related species. Hydrozoans are often characterized by the presence of cryptic species, due to the paucity of available morphological diagnostic characters. Zanclea species are not an exception, showing high genetic divergence compared to a uniform morphology. In this work, the presence of green fluorescence and the morpho-molecular diversity of six coral- and bryozoan-associated Zanclea species from the Maldivian coral reefs were investigated. Specifically, the presence of green fluorescence in polyps and newly released medusae was explored, the general morphology, as well as the cnidome and the interaction with the hosts, were characterized, and the 16S rRNA region was sequenced and analyzed. Overall, Zanclea species showed a similar morphology, with little differences in the general morphological features and in the cnidome. Three of the analyzed species did not show any fluorescence in both life stages. Three other Zanclea species, including two coral-associated cryptic species, were distinguished by species-specific fluorescence patterns in the medusae. Altogether, the results confirmed the morphological similarity despite high genetic divergence in Zanclea species and indicated that fluorescence patterns may be a promising tool in further discriminating closely related and cryptic species. Therefore, the assessment of fluorescence at a large scale in the whole Zancleidae family may be useful to shed light on the diversity of this enigmatic taxon.

scholarly journals Microsatellite loci development and population genetics in Neotropical fish Curimata mivartii (Characiformes: Curimatidae)

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5959 ◽  
Author(s):  
Ricardo M. Landínez-García ◽  
Edna J. Marquez
Keyword(s):  
Population Genetics ◽  
Microsatellite Loci ◽  
Molecular Tools ◽  
Migratory Species ◽  
Lower Section ◽  
Neotropical Fish ◽  
International Union ◽  
Commercially Important ◽  
Species Specific ◽  
Near Threatened

The Curimatidae family plays an ecological role in the recycling and distribution of nutrients and constitutes a major food source for several commercially important fishes. Curimata mivartii, a member of this family, is considered a short-distance migratory species (≤100 km), categorized by the International Union for Conservation of Nature as a near threatened species, based on its declining population densities and habitat disturbance and fragmentation. Since population genetics and species-specific molecular tools remain unknown for all members of the Curimatidae family, this study developed a set of microsatellite loci and studied the population genetics of C. mivartii in the lower section of the Colombian Magdalena-Cauca basin. The results showed high levels of genetic diversity and evidence of gene flow even between locations separated over 350 km. This information provides a baseline for designing conservation and management programs for C.mivartii and constitutes the first study of population genetics in Curimatidae.

Comparative developmental studies using Oscheius/Dolichorhabditis sp. CEW1 (Rhabditidae)

Nematology ◽  
2000 ◽  
Vol 2 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Marie Delattre ◽  
Marie-Laure Dichtel ◽  
Marie-Anne Félix
Keyword(s):  
Caenorhabditis Elegans ◽  
Genetic Analysis ◽  
Precursor Cells ◽  
Developmental Studies ◽  
Morphological Markers ◽  
Molecular Tools ◽  
Ras Gene ◽  
C Elegans ◽  
Vulval Precursor Cells ◽  
Anchor Cell

AbstractIn order to study the evolution of nematode vulva development, we focus on Oscheius/Dolichorhabditis sp. CEW1 (Rhabditidae) in comparison with Caenorhabditis elegans. In this species, the fates of the vulval precursor cells are determined by two successive nested inductions by the uterine anchor cell (instead of a single one in C. elegans). This hermaphroditic species can be cultured and handled like C. elegans. We review vulva development in this species. We present some molecular tools and the sequence of the Ras gene. This species is amenable to genetic analysis and we discuss the isolation of morphological markers. Afin d’étudier l’évolution du développement de la vulve des nématodes, nous nous concentrons sur l’espèce Oscheius/Dolichorhabditis sp. CEW1 (Rhabditidae) en la comparant à Caenorhabditis elegans. Dans cette espèce, les destinées des cellules précurseurs de la vulve sont déterminées par deux inductions emboîtées provenant de la cellule ancre de l’utérus (au lieu d’une seule chez C. elegans). Cette espèce hermaphrodite peut être élévée et manipulée comme C. elegans. Nous décrivons le développement de la vulve dans cette espèce. Nous présentons des outils moléculaires et la séquence du gène Ras. Les analyses génétiques sont possibles dans cette espèce et nous discutons l’isolement de marqueurs morphologiques.

scholarly journals Restoration Scaling Approaches to Addressing Ecological Injury: The Habitat-Based Resource Equivalency Method

2020 ◽  
Vol 65 (2) ◽  
pp. 161-177 ◽  
Author(s):  
Mary Baker ◽  
Adam Domanski ◽  
Terill Hollweg ◽  
Jason Murray ◽  
Diana Lane ◽  
...  
Keyword(s):  
Natural Resource ◽  
Oil Spills ◽  
Error Rates ◽  
Hazardous Substances ◽  
Habitat Equivalency Analysis ◽  
Natural Resource Damage Assessment ◽  
As Species ◽  
Ecological Habitat ◽  
Multiple Species ◽  
Species Specific

AbstractNatural resource trustee agencies must determine how much, and what type of environmental restoration will compensate for injuries to natural resources that result from releases of hazardous substances or oil spills. To fulfill this need, trustees, and other natural resource damage assessment (NRDA) practitioners have relied on a variety of approaches, including habitat equivalency analysis (HEA) and resource equivalency analysis (REA). The purpose of this paper is to introduce the Habitat-Based Resource Equivalency Method (HaBREM), which integrates REA’s reproducible injury metrics and population modeling with HEA’s comprehensive habitat approach to restoration. HaBREM is intended to evaluate injury and restoration using organisms that use the habitat to represent ecological habitat functions. This paper seeks to expand and refine the use of organism-based metrics (biomass-based REA), providing an opportunity to integrate sublethal injuries to multiple species, as well as the potential to include error rates for injury and restoration parameters. Applied by NRDA practitioners in the appropriate context, this methodology can establish the relationship between benefits of compensatory restoration projects and injuries to plant or animal species within an affected habitat. HaBREM may be most effective where there are appropriate data supporting the linkage between habitat and species gains (particularly regionally specific habitat information), as well as species-specific monitoring data and predictions on the growth, density, productivity (i.e., rate of generation of biomass or individuals), and age distributions of indicator species.

scholarly journals Epitypification of Fusarium oxysporum – clearing the taxonomic chaos

2019 ◽  
Vol 43 (1) ◽  
pp. 1-47 ◽  
Author(s):  
L. Lombard ◽  
M. Sandoval-Denis ◽  
S. C. Lamprecht ◽  
P.W. Crous
Keyword(s):  
Fusarium Oxysporum ◽  
Cryptic Species ◽  
Reference Point ◽  
Species Complex ◽  
Phylogenetic Inference ◽  
Classification Systems ◽  
As Species ◽  
Basic Reference ◽  
Cryptic Taxa ◽  
Morphological Differences

Fusarium oxysporum is the most economically important and commonly encountered species of Fusarium. This soil-borne fungus is known to harbour both pathogenic (plant, animal and human) and non-pathogenic strains. However, in its current concept F. oxysporum is a species complex consisting of numerous cryptic species. Identification and naming these cryptic species is complicated by multiple subspecific classification systems and the lack of living ex-type material to serve as basic reference point for phylogenetic inference. Therefore, to advance and stabilise the taxonomic position of F. oxysporum as a species and allow naming of the multiple cryptic species recognised in this species complex, an epitype is designated for F. oxysporum. Using multi-locus phylogenetic inference and subtle morphological differences with the newly established epitype of F. oxysporum as reference point, 15 cryptic taxa are resolved in this study and described as species.

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