| 1. |
- Dedukh, Dmitry, et al.
(författare)
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Cytological maps of lampbrush chromosomes of European water frogs (Pelophylax esculentus complex) from the Eastern Ukraine
- 2013
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Ingår i: BMC Genetics. - : Springer Science and Business Media LLC. - 1471-2156. ; 14, s. 26-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Hybridogenesis (hemiclonal inheritance) is a kind of clonal reproduction in which hybrids between parental species are reproduced by crossing with one of the parental species. European water frogs (Pelophylax esculentus complex) represent an appropriate model for studying interspecies hybridization, processes of hemiclonal inheritance and polyploidization. P. esculentus complex consists of two parental species, P. ridibundus (the lake frog) and P. lessonae (the pool frog), and their hybridogenetic hybrid - P. esculentus (the edible frog). Parental and hybrid frogs can reproduce syntopically and form hemiclonal population systems. For studying mechanisms underlying the maintenance of water frog population systems it is required to characterize the karyotypes transmitted in gametes of parental and different hybrid animals of both sexes. Results: In order to obtain an instrument for characterization of oocyte karyotypes in hybrid female frogs, we constructed cytological maps of lampbrush chromosomes from oocytes of both parental species originating in Eastern Ukraine. We further identified certain molecular components of chromosomal marker structures and mapped coilin-rich spheres and granules, chromosome associated nucleoli and special loops accumulating splicing factors. We recorded the dissimilarities between P. ridibundus and P. lessonae lampbrush chromosomes in the length of orthologous chromosomes, number and location of marker structures and interstitial (TTAGGG)(n)-repeat sites as well as activity of nucleolus organizer. Satellite repeat RrS1 was mapped in centromere regions of lampbrush chromosomes of the both species. Additionally, we discovered transcripts of RrS1 repeat in oocytes of P. ridibundus and P. lessonae. Moreover, G-rich transcripts of telomere repeat were revealed in association with terminal regions of P. ridibundus and P. lessonae lampbrush chromosomes. Conclusions: The constructed cytological maps of lampbrush chromosomes of P. ridibundus and P. lessonae provide basis to define the type of genome transmitted within individual oocytes of P. esculentus females with different ploidy and from various population systems.
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| 2. |
- Dufresnes, Christophe, et al.
(författare)
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Fifteen shades of green : The evolution of Bufotes toads revisited
- 2019
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 141
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Tidskriftsartikel (refereegranskat)abstract
- The radiation of Palearctic green toads (Bufotes) holds great potential to evaluate the role of hybridization in phylogeography at multiple stages along the speciation continuum. With fifteen species representing three ploidy levels, this model system is particularly attractive to examine the causes and consequences of allopoly-ploidization, a prevalent yet enigmatic pathway towards hybrid speciation. Despite substantial efforts, the evolutionary history of this species complex remains largely blurred by the lack of consistency among the corresponding literature. To get a fresh, comprehensive view on Bufotes phylogeography, here we combined genome-wide multilocus analyses (RAD-seq) with an extensive compilation of mitochondrial, genome size, niche modelling, distribution and phenotypic (bioacoustics, morphometrics, toxin composition) datasets, representing hundreds of populations throughout Eurasia. We provide a fully resolved nuclear phylogeny for Bufotes and highlight exceptional cyto-nuclear discordances characteristic of complete mtDNA replacement (in 20% of species), mitochondrial surfing during post-glacial expansions, and the formation of homoploid hybrid populations. Moreover, we traced the origin of several allopolyploids down to species level, showing that all were exclusively fathered by the West Himalayan B. latastii but mothered by several diploid forms inhabiting Central Asian lowlands, an asymmetry consistent with hypotheses on mate choice and Dobzhansky-Muller incompatibilities. Their intermediate call phenotypes potentially allowed for rapid reproductive isolation, while toxin compositions converged towards the ecologically-closest parent. Across the radiation, we pinpoint a stepwise progression of reproductive isolation through time, with a threshold below which hybridizability is irrespective of divergence (< 6My), above which species barely admix and eventually evolve different mating calls (6-10My), or can successfully cross-breed through allopolyploidization (> 15My). Finally, we clarified the taxonomy of Bufotes (including genetic analyses of type series) and formally described two new species, B. cypriensis sp. nov. (endemic to Cyprus) and B. perrini sp. nov. (endemic to Central Asia). Embracing the genomic age, our framework marks the advent of a new exciting era for evolutionary research in these iconic amphibians.
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| 3. |
- Litvinchuk, Spartak N., et al.
(författare)
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Influence of environmental conditions on the distribution of Central Asian green toads with three ploidy levels
- 2011
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Ingår i: Journal of Zoological Systematics and Evolutionary Research. - : Hindawi Limited. - 0947-5745 .- 1439-0469. ; 49:3, s. 233-239
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Tidskriftsartikel (refereegranskat)abstract
- We studied the distribution of Palearctic green toads (Bufo viridis subgroup), an anuran species group with three ploidy levels, inhabiting the Central Asian Amudarya River drainage. Various approaches (one-way, multivariate, components variance analyses and maximum entropy modelling) were used to estimate the effect of altitude, precipitation, temperature and land vegetation covers on the distribution of toads. It is usually assumed that polyploid species occur in regions with harsher climatic conditions (higher latitudes, elevations, etc.), but for the green toads complex, we revealed a more intricate situation. The diploid species (Bufo shaartusiensis and Bufo turanensis) inhabit the arid lowlands (from 44 to 789 m a.s.l.), while tetraploid Bufo pewzowi were recorded in mountainous regions (340-3492 m a.s.l.) with usually lower temperatures and higher precipitation rates than in the region inhabited by diploid species. The triploid species Bufo baturae was found in the Pamirs (Tajikistan) at the highest altitudes (2503-3859 m a.s.l.) under the harshest climatic conditions.
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| 4. |
- Ploetner, Joerg, et al.
(författare)
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Genetic data reveal that water frogs of Cyprus (genus Pelophylax) are an endemic species of Messinian origin
- 2012
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Ingår i: ZOOSYSTEMATICS AND EVOLUTION. - : Wiley. - 1860-0743 .- 1435-1935. ; 88:2, s. 261-283
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Tidskriftsartikel (refereegranskat)abstract
- Water frogs inhabiting Cyprus represent a distinct evolutionary species of Messinian origin that is formally described in this paper. The systematic status of Cypriot frogs is evidenced by specific characters in their mitochondrial (mt) and nuclear (nu) DNA sequences, and the fact that they form a well supported monophyletic clade in both mtDNA and nuDNA phylogenies. While genetic data revealed clear and reproducible differences between this new taxon and all other western Palearctic water frog species including Pelophylax bedriagae in the Levant and two Anatolian water frogs lineages (P. cf. bedriagae -1 and P. cf. bedriagae -2), there is no diagnostic morphological or morphometric character that allows a clear discrimination between Cyprus frogs and frogs from the adjacent mainland. If several morphometric indices are combined as predictor variables in a discriminant analysis, however, both females and males of Cypriot water frogs are correctly distinguished from the other eastern Mediterranean lineages. While phylogenies based on concatenated sequences of two mitochondrial genes (ND2 + ND3) suggest a sister group relationship of Cypriot and Anatolian water frog lineages, our nuclear data hypothesize a sister group relationship between Cypriot frogs (sp. n.) and Crete frogs (P. cretensis), thus speaking for the same isolation time of both island populations.
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| 5. |
- Wagner, Philipp, et al.
(författare)
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Alai! Alai! - a new species of the Gloydius halys (Pallas, 1776) complex (Viperidae, Crotalinae), including a brief review of the complex
- 2016
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Ingår i: Amphibia-Reptilia. - : Brill. - 0173-5373 .- 1568-5381. ; 37:1, s. 15-31
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Tidskriftsartikel (refereegranskat)abstract
- During a scientific field expedition to the Alai-Pamir range five specimens of the genus Gloydius have been collected in the larger Alai. A morphological and genetical examination of the specimens has shown that they are part of the G. halys complex, but represent a new taxon which is characterized by the following unique character combination: It is a slender and moderately stout small snake, up to 479 mm total length. The head has nine symmetrical plates on the upper head, 7 supralabial and 8-9 infralabial scales. Body scales in 20-22 rows around midbody, 143-156 ventral and 35-45 usually paired subcaudal scales. The cloacal plate not divided. The general coloration consists of various different tones of olive, tan and brown, having a distinct head, but an indistinct body pattern with, excluding the tail, 26-29 transverse crossbands, which are not extending to the sides of the body. The haplotype network shows the new species within the G. halys complex and close related to both, G. h. halys and G. h. caraganus. So far the new described species is only known from the Alai range. However, various Gloydius specimens are found in Kyrgyzstan and because of the complicated taxonomy those specimens have to re-identified to clarify their status and the status of the new species.
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