Unique issues of the species concept in molluscs of the genus Corbicula: a mismatch of mitochondrial and nuclear genomes

2021 ◽  
pp. 274-280
Author(s):  
Halyna Morhun ◽  
Mikhail Son ◽  
Serge Utevsky
Keyword(s):  
Nucleotide Diversity ◽  
Species Concept ◽  
Genetic Material ◽  
Oocyte Nucleus ◽  
Phylogenetic Species ◽  
Separate Species ◽  
Brackish Waters ◽  
Invasive Bivalves ◽  
Wide Range ◽  
Egg Parasitism

Molluscs of the genus Corbicula are well-known invasive bivalves found all over the world. These ecologically important clams are characterised by a wide range of habitats (both brackish waters and freshwater environments) and by contrasting modes of reproduction in native ranges (including sexual and asexual modes) and in invasive ranges (asexual mode). The asexual freshwater Corbicula reproduces through androgenetic fertilization, also termed “egg parasitism”, where the oocyte nucleus is replaced by the spermatozoon nucleus, yet the mitochondria are inherited from the mother cell. This results in a mismatch between the genetic material of the nucleus and mitochondria (and, accordingly, with the external morphology of the shell). In addition, the low nucleotide diversity in the genus Corbicula challenges the delimitation of separate species, thus it is difficult to apply the traditional taxonomic and phylogenetic species criteria to Corbicula populations.

scholarly journals Low-Energy Electron Damage to Condensed-Phase DNA and Its Constituents

2021 ◽  
Vol 22 (15) ◽  
pp. 7879
Author(s):  
Yingxia Gao ◽  
Yi Zheng ◽  
Léon Sanche
Keyword(s):  
Condensed Phase ◽  
Genetic Material ◽  
High Energy ◽  
Dna Lesions ◽  
Low Energy ◽  
Experimental Investigations ◽  
Experimental Conditions ◽  
Strand Breaks ◽  
Sequence Of Events ◽  
Wide Range

The complex physical and chemical reactions between the large number of low-energy (0–30 eV) electrons (LEEs) released by high energy radiation interacting with genetic material can lead to the formation of various DNA lesions such as crosslinks, single strand breaks, base modifications, and cleavage, as well as double strand breaks and other cluster damages. When crosslinks and cluster damages cannot be repaired by the cell, they can cause genetic loss of information, mutations, apoptosis, and promote genomic instability. Through the efforts of many research groups in the past two decades, the study of the interaction between LEEs and DNA under different experimental conditions has unveiled some of the main mechanisms responsible for these damages. In the present review, we focus on experimental investigations in the condensed phase that range from fundamental DNA constituents to oligonucleotides, synthetic duplex DNA, and bacterial (i.e., plasmid) DNA. These targets were irradiated either with LEEs from a monoenergetic-electron or photoelectron source, as sub-monolayer, monolayer, or multilayer films and within clusters or water solutions. Each type of experiment is briefly described, and the observed DNA damages are reported, along with the proposed mechanisms. Defining the role of LEEs within the sequence of events leading to radiobiological lesions contributes to our understanding of the action of radiation on living organisms, over a wide range of initial radiation energies. Applications of the interaction of LEEs with DNA to radiotherapy are briefly summarized.

Subspecies definitions and legislation: from eastern wallaroo (Osphranter robustus robustus) to euro (Osphranter robustus erubescens)

2019 ◽  
Vol 41 (1) ◽  
pp. 65 ◽  
Author(s):  
Barry J. Richardson
Keyword(s):  
Species Concept ◽  
Genetic Data ◽  
Ecological Approach ◽  
Phylogenetic Species ◽  
Management Decisions ◽  
Evolutionary Trajectory ◽  
Genetic Studies ◽  
Phylogenetic Species Concept ◽  
Population Structuring ◽  
Traditional Approaches

As a consequence of genetic studies of population structuring, the usefulness of subspecies has been questioned, with opinions divided. The situation is further confused by the use of varying species and subspecies concepts. Most alternatives require each taxon to be following an independent evolutionary trajectory. These include traditional approaches and the more recent phylogenetic species concept. The latter has led to large increases in the apparent number of taxa in some groups, though strong objections have been raised to this approach. An alternative, the ecological species concept, has been opposed by phylogeneticists. These two approaches are compared using morphological and genetic data from common wallaroo (Osphranter robustus) populations. The different taxonomies that might result (many species, one species with two subspecies, one species with no subspecies) can have significant consequences for legislative and management decisions. The ecological approach is considered preferable for subspecies and the present taxonomy is maintained. A potential location of the boundary between the wallaroo subspecies is proposed. How the use of the different subspecies definitions would affect legislative decisions is explored.

scholarly journals Genetic divergence in mitochondrial DNA of Anopheles nuneztovari (Diptera: Culicidae) from Brazil and Colombia

2000 ◽  
Vol 23 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Vera Margarete Scarpassa ◽  
Silvia Geurgas ◽  
Ana Maria L. Azeredo-Espin ◽  
Wanderli Pedro Tadei
Keyword(s):  
Mitochondrial Dna ◽  
Genetic Divergence ◽  
Nucleotide Diversity ◽  
Haplotype Diversity ◽  
Sequence Divergence ◽  
Brazilian Amazon ◽  
Restriction Endonucleases ◽  
Separate Species ◽  
Geographic Populations

In the present study, we have examined the variability in Anopheles nuneztovari mitochondrial DNA of three populations from the Brazilian Amazon and one from western Colombia (Sitronela), using four restriction endonucleases (BclI, ClaI, HindIII, SstI). The haplotype diversity (h) was slightly elevated in all populations (0.5000 to 0.6765), whereas the nucleotide diversity (pi) was lower in the Sitronela population (0.0029) and higher in populations from the Brazilian Amazon (0.0056 to 0.0098). The degree of sequence divergence (delta) estimated within the Brazilian Amazon and that in Sitronela (0.0329 to 0.0371) suggests that these geographic populations of A. nuneztovari may eventually constitute separate species. The low sequence divergence values among the three Brazilian Amazon populations (0.0012 to 0.0031) indicate that these populations are genetically similar. These results are consistent with those recently reported for allozymes of these same populations.

scholarly journals Changes in Fish Taxonomy Affect Freshwater Biogeographical Regionalisations: Insights from Greece

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1743 ◽  
Author(s):  
Vavalidis ◽  
Zogaris ◽  
Economou ◽  
Kallimanis ◽  
Bobori
Keyword(s):  
Numerical Taxonomy ◽  
Species Concept ◽  
Regional Scale ◽  
Fish Fauna ◽  
Phylogenetic Species ◽  
Phylogenetic Species Concept ◽  
Cluster Analyses ◽  
Fish Taxonomy ◽  
Region Scale ◽  
Key Indicators

Freshwater fishes are key indicators for delineating biogeographical maps worldwide. However, controversy in regional-scale ichthyogeographic boundaries still persists, especially in areas of high species endemicity, such as in Greece. One problem concerns the taxonomy of the fishes because there have been extensive changes, mainly due to an increased splitting of species in recent years in Europe. Here, we explore why ichthyogeographic boundary disagreements and uncertainties in region-scale biogeographical units persist. We compare cluster analyses of river basin fish fauna in Greece using two taxonomic datasets: the older fish taxonomy (from 1991) and the current taxonomy that now follows the phylogenetic species concept (PSC), which has become widely established in Europe after 2007. Cluster analyses using the older fish taxonomy depicts only two major biogeographical regional divisions, while the current taxonomy defines four major regional divisions in mainland Greece. Interestingly, some older maps from the pre-PSC taxonomy era also similarly show four ichthyogeographic divisions in Greece and we can assume that the older biogeographical work did not solely use numerical taxonomy but followed an expert-guided synthesis; the older regional definitions have persisted quite well despite radical changes in Europe’s fish taxonomy. Through the prism of biodiversity conservation planning, we hope this review may help identify ways to help standardize policy-relevant biogeographical mapping.

A minimalist macroparasite diversity in the round goby of the Upper Rhine reduced to an exotic acanthocephalan lineage

Parasitology ◽  
2017 ◽  
Vol 145 (8) ◽  
pp. 1020-1026 ◽  
Author(s):  
Gwendoline M. David ◽  
Cybill Staentzel ◽  
Olivier Schlumberger ◽  
Marie-Jeanne Perrot-Minnot ◽  
Jean-Nicolas Beisel ◽  
...  
Keyword(s):  
Western Europe ◽  
Nucleotide Diversity ◽  
Round Goby ◽  
Haplotype Diversity ◽  
Neogobius Melanostomus ◽  
Molecular Barcoding ◽  
Wide Range ◽  
Using Data ◽  
Upper Rhine ◽  
Invasion Corridor

AbstractThe round goby, Neogobius melanostomus, is a Ponto-Caspian fish considered as an invasive species in a wide range of aquatic ecosystems. To understand the role that parasites may play in its successful invasion across Western Europe, we investigated the parasitic diversity of the round goby along its invasion corridor, from the Danube to the Upper Rhine rivers, using data from literature and a molecular barcoding approach, respectively. Among 1666 parasites extracted from 179 gobies of the Upper Rhine, all of the 248 parasites barcoded on the c oxidase subunit I gene were identified as Pomphorhynchus laevis. This lack of macroparasite diversity was interpreted as a loss of parasites along its invasion corridor without spillback compensation. The genetic diversity of P. laevis was represented by 33 haplotypes corresponding to a haplotype diversity of 0·65 ± 0·032, but a weak nucleotide diversity of 0·0018 ± 0·00015. Eight of these haplotypes were found in 88·4% of the 248 parasites. These haplotypes belong to a single lineage so far restricted to the Danube, Vistula and Volga rivers (Eastern Europe). This result underlines the exotic status of this Ponto-Caspian lineage in the Upper Rhine, putatively disseminated by the round goby along its invasion corridor.

Revison of the Tasmanian genus of freshwater crayfish Astacopsis Huxley (Decapoda : Parastacidae)

1982 ◽  
Vol 33 (4) ◽  
pp. 699 ◽  
Author(s):  
R Swain ◽  
AMM Richardson ◽  
M Hortle
Keyword(s):  
Geographical Distribution ◽  
Morphological Characters ◽  
Species Boundaries ◽  
Freshwater Crayfish ◽  
Separate Species ◽  
Drainage Systems ◽  
Number Of Species ◽  
Wide Range ◽  
Animal Size

Astacopsis Huxley is revised by examination of a wide range of morphological characters. The number of species is reduced from four to two by synonymy. Variation in spination is examined in A. franklinii in relation to geographical distribution (based upon the major drainage systems in Tasmania), animal size and habitat; spininess is found to relate predominantly to animal size. The distribution of Astacopsis within Tasmania is greatly extended and previous reports of geographically separate species' boundaries, indicating limited distributions. can no longer be accepted. Synonymies and diagnoses are provided for A. franklinii and A. gouldi, and a key to their identification is presented.

64 CRYOPRESERVATION OF CAT OVARIAN TISSUE BY VITRIFICATION

2013 ◽  
Vol 25 (1) ◽  
pp. 179 ◽  
Author(s):  
J. Galiguis ◽  
C. E. Pope ◽  
M. C. Gómez ◽  
C. Dumas ◽  
S. P. Leibo
Keyword(s):  
Ethylene Glycol ◽  
Dimethyl Sulfoxide ◽  
Ovarian Tissue ◽  
Genetic Material ◽  
Cortical Tissue ◽  
Rock Inhibitor ◽  
Tissue Samples ◽  
Preantral Follicles ◽  
Wide Range ◽  
Chi Square Analysis

The cryopreservation of ovarian tissue is linked to a wide range of possible applications, from oocyte harvesting to allo- and xenotransplantation. These procedures have significant potential for the preservation of valuable genetic material and endangered-species conservation. The objectives of the present study were to (1) compare viability of preantral follicles obtained from fresh v. vitrified feline ovarian cortex, (2) evaluate the effect of apoptotic inhibitors (ROCK inhibitor v. glutathione) on viability of follicles from vitrified samples, and (3) determine the optimal inhibitor concentration for follicle viability. In Experiment 1, 5 × 5 × 1 mm cortical tissue samples were obtained from excised cat ovaries and assigned to either the fresh control or vitrification group. Fresh samples were processed through a 230-micron-pore dissection strainer to collect preantral follicles. Follicles were then stained in Trypan blue to determine membrane integrity and survival rates. Vitrification samples were first equilibrated in 7.5% dimethyl sulfoxide and 7.5% ethylene glycol at ~22°C and then in vitrification solution consisting of 20% dimethyl sulfoxide, 20% ethylene glycol, and 0.5 M sucrose. They were then vitrified on a thin, perforated, metal strip (Cryotissue, Kitazato Biopharma, Fujinomiya, Japan). Samples were later warmed in 1.0 M sucrose at 38°C. Follicles were then collected and assessed for survival. In Experiment 2, follicles were collected from samples vitrified/warmed in cryo-media supplemented with either 3 × 104 nM ROCK inhibitor or 6 nM glutathione. Follicles from samples vitrified/warmed without inhibitor treatment were used as controls. In Experiment 3, tissue samples were vitrified/warmed in cryo-media supplemented with 0, 2, 6, or 10 nM glutathione before follicle viability was determined. Data were evaluated by chi square analysis. In Experiment 1, 637 and 340 follicles were collected from fresh and vitrified samples, respectively. Overall, survival was higher in freshly collected follicles when compared to those from the vitrified group (67 v. 18%, respectively; P < 0.05). Evaluation of apoptotic inhibitors was determined through collection of 314, 354, and 506 follicles from inhibitor-free, ROCK inhibitor, and glutathione-treated media, respectively. Follicles from samples vitrified in inhibitor-free media and in ROCK inhibitor survived at a lower rate than those from glutathione-treated samples (10 and 13% v. 18%, respectively; P < 0.05). In Experiment 3, a total of 539, 641, 625, and 632 follicles were collected from samples treated in 0, 2, 6, and 10 nM glutathione, respectively. There were no statistical differences in follicle survival among the 0, 2, and 6 nM groups. However, follicles treated in 10 nM glutathione survived at a higher rate than those vitrified/warmed in the absence of glutathione (20 v. 14%; P < 0.05). In summary, viability of preantral follicles from ovarian cortical tissue was significantly reduced by vitrification. Despite this, tolerance of such follicles to cryopreservation was improved by vitrifying and warming in cryo-media containing 10 nM glutathione. Partially funded by the LSU/ACRES Collaborative Project.

scholarly journals The Biology of Crangon Vulgaris L. in the Bristol Channel and Severn Estuary

1947 ◽  
Vol 26 (4) ◽  
pp. 626-661 ◽  
Author(s):  
A. J. Lloyd ◽  
C. M. Yonge
Keyword(s):  
Low Temperatures ◽  
Egg Laying ◽  
Sexual Cycle ◽  
Minimum Length ◽  
Severn Estuary ◽  
Brackish Waters ◽  
Low Salinity ◽  
Egg Carrying ◽  
Wide Range ◽  
Shrimp Fisheries

Collections of some 22,000 female and 6000 male Crangon vulgaris were made throughout the year from the shrimp fisheries of the Severn Estuary and Bristol Channel. All animals were measured.The habits of the species are described; it can withstand a wide range of temperature but, though euryhaline, resembles other Decapoda in the inability to withstand low salinity combined with low temperature.Osmo-regulation is apparently largely inhibited at low temperatures and to a greater extent in the males than the females.Growth rate decreases with increasing age; in the female there is no increase in length when moulting from the ' neuter' to the egg-carrying intermoult. The duration of this intermoult, if spawning is successful, is about double that of the normal intermoult under the same temperature conditions. Growth almost ceases in the winter.Secondary sexual characters are described, especially the differences between the endopodites of the pleopods in the two sexes.Females become mature at a minimum length of 45 mm. in the Channel and seldom less than 50 mm. in the Estuary. The effect of the female sexual cycle on the size of the ovary and the form of the pleopods is described. The process of copulation is described; it can occur in the brackish waters of the estuary. Egg-laying always follows within two days of moulting into the egg-carrying condition but eggs are not retained if copulation has not occurred.The females lie on their sides during the act of spawning and the eggs are firmly attached within thirty minutes to the egg-carrying setae on the basipodites of the first to fourth pair of pleopods, then to those on the endopodite of the first pleopod, finally to those on the coxopodites of the last two pairs of pereiopods.

Responses of wheat to vernalization and photoperiod

1985 ◽  
Vol 36 (3) ◽  
pp. 347 ◽  
Author(s):  
JL Davidson ◽  
KR Christian ◽  
DB Jones ◽  
PM Bremner
Keyword(s):  
Flowering Time ◽  
Broad Spectrum ◽  
Narrow Range ◽  
Genetic Material ◽  
High Rainfall ◽  
Wide Range

The effects of vernalization and photoperiod on times from planting of seedlings to ear emergence were measured in 68 Australian and 49 overseas varieties of wheat, comprising a broad spectrum of genetic material, in a glasshouse in Canberra (latitude 35�S). Vernalization was carried out by growing germinated seedlings in the dark at 1-2�C for 6 weeks. Long photoperiods (16 h) separated unvernalized plants into two distinct groups, corresponding to commonly recognized spring and winter types. Responses to vernalization were generally small under natural photoperiods (11-15 h), but much more pronounced in long photoperiods, particularly with winter wheats. In a second experiment, 24 varieties of wheat gave widely different responses to vernalization treatments. With 8 weeks' vernalization and long photoperiods, all varieties reached ear emergence within 66 days, but in some winter wheats 4 weeks treatment had little effect and 6 weeks gave incomplete vernalization. Under the conditions of these experiments, Australian wheats showed a wide range of responses to photoperiod and a narrow range of responses to vernalization compared with overseas varieties. The need to investigate the control of flowering time in obtaining varieties suited to the high-rainfall zone of Australia is discussed.

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