geographic range Dotaz Zobrazit nápovědu
Range size heritability refers to an intriguing pattern where closely related species occupy geographic ranges of similar extent. Its existence may indicate selection on traits emergent only at the species level, with interesting consequences for evolutionary processes. We explore whether range size heritability may be attributable to the fact that range size is largely driven by the size of geographic domains (i.e., continents, biomes, areas given by species' climatic tolerance) that tend to be similar in phylogenetically related species. Using a well-resolved phylogeny of Carnivora, we show that range sizes are indeed constrained by geographic domains and that the phylogenetic signal in range sizes diminishes if the domain sizes are accounted for. Moreover, more detailed delimitation of species' geographic domain leads to a weaker signal in range size heritability, indicating the importance of definition of the null model against which the pattern is tested. Our findings do not reject the hypothesis of range size heritability but rather unravel its underlying mechanisms. Additional analyses imply that evolutionary conservatism in niche breadth delimits the species' geographic domain, which in turn shapes the species' range size. Range size heritability patterns thus emerge as a consequence of this interplay between evolutionary and geographic constraints.
Genetic diversity is important for species' fitness and evolutionary processes but our knowledge on how it varies across a species' distribution range is limited. The abundant centre hypothesis (ACH) predicts that populations become smaller and more isolated towards the geographic range periphery - a pattern that in turn should be associated with decreasing genetic diversity and increasing genetic differentiation. We tested this hypothesis in Adonis vernalis, a dry grassland plant with an extensive Eurasian distribution. Its life-history traits and distribution characteristics suggest a low genetic diversity that decreases and a high genetic differentiation that increases towards the range edge. We analysed AFLP fingerprints in 28 populations along a 4698-km transect from the geographic range core in Russia to the western range periphery in Central and Western Europe. Contrary to our expectation, our analysis revealed high genetic diversity (range of proportion of polymorphic bands = 56-81%, He = 0.168-0.238) and low genetic differentiation across populations (Φ(ST) = 0.18). However, in congruence with the genetic predictions of the ACH, genetic diversity decreased and genetic differentiation increased towards the range periphery. Spanish populations were genetically distinct, suggesting a divergent post-glacial history in this region. The high genetic diversity and low genetic differentiation in the remaining A. vernalis populations is surprising given the species' life-history traits and points to the possibility that the species has been widely distributed in the studied region or that it has migrated from a diverse source in an East-West direction, in the past.
- MeSH
- distribuce rostlin * MeSH
- fylogeneze MeSH
- fylogeografie * MeSH
- genetická variace * MeSH
- genetický drift MeSH
- hlaváček genetika MeSH
- ledový příkrov MeSH
- mikrosatelitní repetice MeSH
- pastviny * MeSH
- polymorfismus genetický MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Španělsko MeSH
Polyploidisation has played an important role in plant diversification, and variation in ploidy level may be found not only between species of the same genus, but also within a single species. Although establishing the adaptive significance of polyploidy to explain the geographic distribution of cytotypes is challenging, the occurrence of different cytotypes in different ecological niches may suggest an adaptive role of genome duplication. We studied the adaptive significance of the geographic distribution of cytotypes across the entire distribution range of the endemic Erysimum mediohispanicum (Brassicaceae). For that, we have used climate variables, population elevation and soil properties to model ecological niches for the different cytotypes. In addition, we analysed the effect that ploidy level has on the floral phenotype. We found a clear geographic pattern in the distribution of cytotypes, with diploid individuals occurring in the southernmost part of the distribution range, while tetraploids were found in the northern area. A contact (mosaic) zone between both cytotypes was identified, but diploids and tetraploids occur in sympatry in only one population (although in a highly unbalanced proportion). Gene flow between different cytotypes seems to be negligible, as evident from an almost complete absence of triploids and other minority cytotypes. Niches occupied by both cytotypes showed subtle, but significant differences, even in the contact zone. Precipitation was higher in regions occupied by tetraploid individuals, which present wider corolla tubes and thinner but taller stalks than diploids. Our findings highlight the potential role of polyploidy in the ecological adaptation of E. mediohispanicum to both abiotic factors and biotic interactions.
Successful co-introduction of a parasite and its host relies not only on presence of the parasite on host individuals in the founder population but also on the ability of both host and parasite to persist in the new area. Gyrodactylus proterorhini (Monogenea) has been successfully co-introduced with its Ponto-Caspian goby hosts (Babka gymnotrachelus, Neogobius fluviatilis, Neogobius melanostomus, Ponticola kessleri, Proterorhinus semilunaris) to many freshwater systems in Europe and is now widely distributed over four large European river basins (Danube, Rhine, Scheldt and Vistula). Within Europe, higher infection levels are documented in sites further from the native host range. In North America, however, G. proterorhini appears to be absent. Host specificity of G. proterorhini tested under natural conditions showed accidental host-switching onto local fish species (native Perca fluviatilis and non-native Perccottus glenii) in the river Vistula. Further examination of host-switching under experimental conditions, however, showed that G. proterorhini were unable to survive on non-gobiid hosts longer than 24 h. Our results indicate extremely low potential for host-switching of introduced G. proterorhini to non-gobiid hosts, at least in the freshwater systems of Central and Western Europe.
- MeSH
- hostitelská specificita fyziologie MeSH
- infekce červy třídy Trematoda epidemiologie parazitologie veterinární MeSH
- Perciformes parazitologie MeSH
- řeky parazitologie MeSH
- Trematoda izolace a purifikace MeSH
- zeměpis MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Evropa epidemiologie MeSH
- Severní Amerika epidemiologie MeSH
Circadian clocks keep organisms in synchrony with external day-night cycles. The free running period (FRP) of the clock, however, is usually only close to-not exactly-24 h. Here, we explored the geographical variation in the FRP of the linden bug, Pyrrhocoris apterus, in 59 field-lines originating from a wide variety of localities representing geographically different environments. We have identified a remarkable range in the FRPs between field-lines, with the fastest clock at ~21 h and the slowest close to 28 h, a range comparable to the collections of clock mutants in model organisms. Similarly, field-lines differed in the percentage of rhythmic individuals, with a minimum of 13.8% and a maximum of 86.8%. Although the FRP correlates with the latitude and perhaps with the altitude of the locality, the actual function of this FRP diversity is currently unclear. With the recent technological progress of massive parallel sequencing and genome editing, we can expect remarkable progress in elucidating the genetic basis of similar geographic variants in P. apterus or in similar emerging model species of chronobiology.
- MeSH
- časové faktory MeSH
- cirkadiánní hodiny fyziologie MeSH
- cirkadiánní rytmus fyziologie MeSH
- fylogeneze MeSH
- Heteroptera klasifikace genetika fyziologie MeSH
- pohybová aktivita fyziologie MeSH
- Tilia parazitologie MeSH
- zeměpis MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Geografické názvy
- Evropa MeSH
- Izrael MeSH
- východní Evropa MeSH
The decline of amphibian populations, particularly frogs, is often cited as an example in support of the claim that Earth is undergoing its sixth mass extinction event. Amphibians seem to be particularly sensitive to emerging diseases (e.g., fungal and viral pathogens), yet the diversity and geographic distribution of infectious agents are only starting to be investigated. Recent work has linked a previously undescribed protist with mass-mortality events in the United States, in which infected frog tadpoles have an abnormally enlarged yellowish liver filled with protist cells of a presumed parasite. Phylogenetic analyses revealed that this infectious agent was affiliated with the Perkinsea: a parasitic group within the alveolates exemplified by Perkinsus sp., a "marine" protist responsible for mass-mortality events in commercial shellfish populations. Using small subunit (SSU) ribosomal DNA (rDNA) sequencing, we developed a targeted PCR protocol for preferentially sampling a clade of the Perkinsea. We tested this protocol on freshwater environmental DNA, revealing a wide diversity of Perkinsea lineages in these environments. Then, we used the same protocol to test for Perkinsea-like lineages in livers of 182 tadpoles from multiple families of frogs. We identified a distinct Perkinsea clade, encompassing a low level of SSU rDNA variation different from the lineage previously associated with tadpole mass-mortality events. Members of this clade were present in 38 tadpoles sampled from 14 distinct genera/phylogroups, from five countries across three continents. These data provide, to our knowledge, the first evidence that Perkinsea-like protists infect tadpoles across a wide taxonomic range of frogs in tropical and temperate environments, including oceanic islands.
Dermacentor parumapertus Neumann (Acari: Ixodidae), a tick primarily associated with rabbits which occurs over much of the western United States, has a fairly large north-to-south distribution, being found from central Idaho southward into northern Mexico. This mostly obscure tick species has recently been the focus of attention due to the discovery of a unique strain of Rickettsia parkeri associated with it which appears closely related to a Rickettsia sp. found in the Atlantic rainforest of Brazil. Historically, a morphological variety of this species was reported in the literature based on significant variation in ornamentation of the tick throughout its range. This study examines several key morphological characters to determine if there are indeed more than one distinct population of this species throughout its range.
- MeSH
- Dermacentor anatomie a histologie klasifikace MeSH
- rozšíření zvířat MeSH
- zeměpis MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- jihozápad USA MeSH
- Mexiko MeSH
Úvod: Transplantace srdce (TxS) je poslední terapeutickou možností v léčbě terminálního srdečního selhání. Geografické rozdíly v incidenci TxS mohou svědčit pro zhoršenou dostupnost zdravotní péče v některých regionech. Cílem studie bylo zhodnotit regionální distribuci TxS v České republice. Metody: Provedli jsme retrospektivní analýzu všech pacientů, kterým byla v období od 1. 1. 2008 do 30. 9. 2013 provedena v České republice TxS, a určili jsme incidenci TxS ve všech okresech a krajích. Dále jsme studovali, zda jsou zjištěné rozdíly ve vztahu k vybraným geografickým, demografickým nebo socioekonomickým faktorům a zda souvisejí s prevalencí ischemické choroby srdeční (ICHS) a diabetes mellitus (DM). Výsledky: V České republice jsou dvě centra provádějící transplantace srdce, v nichž bylo během výše zmíněného období provedeno 496 TxS (odpovídá 8,211 TxS na rok a milion obyvatel). Na úrovni krajů byla incidence TxS mezi 4,4 a 12,2 na rok a milion obyvatel bez statisticky signifikantního rozdílu. Na úrovni okresů byly rozdíly v incidenci TxS statisticky významné (p < 0,0001). Statistická významnost byla způsobena vysokou incidencí TxS v šesti okresech (ze sedmdesáti sedmi). Incidence TxS nesouvisela se vzdáleností do nejbližšího transplantačního centra (p = 0,09 pro okresy, p = 0,28 pro kraje) a byla podobná v krajích s komplexním kardiovaskulárním centrem i bez něj (7,77 ± 2,17 vs. 7,94 ± 1,54, p = 0,87 na rok a milion obyvatel). Incidence TxS nesouvisela s počtem hospitalizací pro ICHS na úrovni krajů (p = 0,78), s počtem pacientů s DM (rovněž na úrovni krajů, p = 0,10), s procentuálním zastoupením můžu jak na úrovní krajů (p = 0,32), tak okresů (p = 0,76) ani s věkem obyvatel (p = 0,79 pro kraje, p = 0,42 pro okresy). Incidence TxS nesouvisela ani s průměrným výdělkem v krajích (p = 0,30), ani s mírou nezaměstnanosti jak na úrovni okresů (p = 0,76), tak krajů (p = 0,89). Závěr: Incidence TxS je v České republice na úrovni krajů rovnoměrně rozložena. Nebylo zjištěno, že by byl nějaký kraj v České republice znevýhodněn v dostupnosti tohoto komplikovaného léčebného zákroku. Variabilita incidence TxS na úrovni krajů byla nezávislá na věku, pohlaví, incidenci ICHS a DM, nebyla rovněž zjištěna souvislost s příjmem ani s mírou nezaměstnanosti.
Background: Heart transplantation (HTx) is the last resort therapeutic option in management of end-stage heart failure (HF). Geographic variation in incidence of HTx may disclose regional bias in the access to health care. The purpose of the study was to evaluate regional distribution of HTx in the Czech Republic. Methods: We retrospectively analyzed data from all patients who underwent HTx in the Czech Republic between 1. 1. 2008 and 30. 9. 2013 and determined the incidence of HTx in all counties (“okresy”) and higher administrative regions (“kraje”). In addition, we determined whether such regional incidence of HTx was related to geographical, demographic, socioeconomic factors or regional variation in coronary artery disease (CAD) or diabetes mellitus (DM) prevalence. Results: Within the period above, 496 HTx were performed in the only two national transplant centers (8.211 per year and million inhabitants). Their regional incidence ranged between 4.4 and 12.2 per year and million inhabitants without a significant difference. On the level of counties, difference in HTx incidence was statistically significant (p < 0.0001) with six counties out of seventy-seven being responsible for uneven distribution. The incidence of HTx was not related to the distance to the nearest HTx center (p = 0.09 for counties, p = 0.28 for regions) and was similar in regions with and without a complex cardiovascular center (7.77 ± 2.17 vs. 7.94 ± 1.56, p = 0.87 per year and million inhabitants). Interestingly, the incidence of HTx was unrelated to the number of hospitalizations for CAD in regions (p = 0.78), number of patients with DM in regions (p = 0.10), percentage of males both in regions (p = 0.32) and counties (p = 0.76) and age of population (p = 0.79 for regions, p = 0.42 for counties). HTx incidence also did not correlate with average salary in regions (p = 0.30) and unemployment rate both in counties (p = 0.76) and regions (p = 0.89). Conclusion: Regional incidence of HTx was found evenly spread throughout regions, indicating no geographic restrictions in access to this advanced therapy in the Czech Republic. The variation in regional HTx incidence was unrelated to average regional age, gender, incidence of CAD or DM, income or unemployment rate.
- MeSH
- dostupnost zdravotnických služeb * statistika a číselné údaje MeSH
- incidence MeSH
- lidé MeSH
- řízení zdravotnictví MeSH
- socioekonomické faktory MeSH
- statistika přirozeného pohybu MeSH
- transplantace srdce * statistika a číselné údaje MeSH
- výzkum zdravotnických služeb statistika a číselné údaje MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Miller's Grizzled Langur (Presbytis hosei canicrus) is one of the least known and rarest primates in Borneo. With a limited geographic range along the central coast of East Kalimantan and the highly degraded Kutai National Park, its former stronghold, this subspecies is now extremely rare and has been listed as one of the world's 25 most endangered primates. From June 6 to August 2, 2011, we carried out both direct observation and camera trap surveys at two mineral springs (sepans) in the Wehea Forest, East Kutai district, East Kalimantan. Presbytis hosei canicrus was observed at the large sepan on 3 of 6 observation days and at the small sepan on 2 of 3 observation days with up to 11 individuals observed in a single day at a single site. Camera traps recorded a per day capture rate of 0.72 at the small sepan and 0.25 at the large sepan and a per photo capture rate of 0.50 and 0.005, respectively. These data suggest relatively frequent occurrence of P. h. canicrus at the sepans, but the langurs are rarely encountered elsewhere in the Wehea Forest. The discovery of P. h. canicrus in the Wehea Forest confirms the continued existence of this endangered primate and is the first solid evidence demonstrating that its geographic range extends further inland than previously thought. It is not known whether the population of P. h. canicrus within Wehea Forest is large and stable enough to be considered viable, but it is likely part of a larger population that may possibly occur across surrounding protected forests and logging concessions. Surveying this potentially large population, and securing its protection, should be a priority measure for ensuring the continued existence of P. h. canicrus.
- MeSH
- Cercopithecidae * MeSH
- ohrožené druhy statistika a číselné údaje MeSH
- přírodní prameny MeSH
- zeměpis MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Indonésie MeSH
