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A case of natural triploidy in European diploid green toad (Bufo viridis), with some distributional records of diploid and tetraploid toads
(Russian Journal of Herpetology, 2007) Borkin, L.J.; Shabanov, D.A.; Brandler, O.V.; Kukushkin, O.V.; Litvinchuk, S.N.; Mazepa, G.A.; Rosanov, J.M.
A triploid female (3n = 33) was found in diploid species Bufo viridis from the Crimea Peninsula, Ukraine. The case is recognized as an occasional autotriploidy. No morphological differences were found between this triploid female and other diploid specimens of the sample. Three categories of triploids in the Bufo viridis group are classified. Based on six green toad samples identified by chromosome number, the distribution of diploid and polyploid toads in Kazakhstan is discussed.
Crossing experiments reveal gamete contribution into appearance of di-and triploid hybrid frogs in Pelophylax esculentus population systems
(Chromosome Research, 2015) Dedukh, D.V.; Litvinchuk, S.N.; Rosanov, J.M.; Shabanov, D.A.; Krasikova, A.K.
Speciation through hybridization is connected with appearance of interspecies hybrids which can survive and reproduce owing to changes in their gametogenesis. In animals, these changes lead to appearance of clonal animals, which for successful reproduction usually depend on parental species and lack of recombination during gamete formation. Polyploidization can resolve these problems and may lead to emergence of new species. Pelophylax esculentus complex (complex of European water frogs) represents one of the appropriate models for studying interspecies hybridization and processes of polyploidization. Hybrid nature of the P. esculentus (RL genotype, 2n=26) was confirmed after crossings of two parental species P. ridibundus (RR genotype, 2n=26) and P. lessonae (LL genotype, 2n=26). Nevertheless absence of one parental species (P. lessonae) and abundance of triploid hybrid frogs (RRL and LLR genotypes, 3n=39) in population systems at the East of Ukraine challenged us to understand how di- and triploid hybrids can appear and prosper in population systems where hybrids exist only with P. ridibundus (R-E type population system). To answer this question we performed cytogenetic analysis of tadpoles appeared after artificial crossing experiments of diploid and triploid hybrids. Moreover, we identified karyotypes transmitted in growing oocytes of females participated in the crossings. Genome composition of mature frogs and tadpoles was established using FISH revealing interstitial (TTAGGG)n repeat sites that differed in two parental species. After crossings of six triploid hybrid females with RRL genotype and one female with LLR genotype with diploid hybrid males and triploid hybrid males with RRL genotype, tadpoles with karyotypes corresponding to P. ridibundus karyotypeappeared.Lampbrushchromosomesobtainedfrom oocytes of all triploid females participated in the crossings were represented by 13 bivalents corresponding to P. ridibundus chromosomes. Analysis of lampbrush chromosomes from oocytes of additional 11 hybrid females with RRL genome composition also revealed oocytes with 13 bivalents corresponding to P. ridibundus chromosomes. We suppose that such oocytes can overcome meiosis and form haploid gametes withP. ridibundusgenome. After crossings oftwo pairs of diploid hybrids we obtained triploid tadpoles with RRL andLLRkaryotypes.Oocytesfromdiploidhybrid females participated in the crossing and four additional diploid hybrid females contained 26 bivalents corresponding to P. ridibundus and P. lessonae chromosomes.Suchoocytespresumablycanformdiploidgametes after meiotic division. One diploid female after crossing with P. ridibundus male produced both P. ridibundus and diploid P. esculentus tadpoles and had oocytes with 26 bivalents corresponding to P. ridibundus and P. lessonae chromosomes. Other six diploid hybrid females had oocytes with 13 bivalents corresponding to P. ridibundus chromosomes. Crossings of seven diploid males with P. ridibundus females or triploid females with RRL genome composition resulted in appearance of tadpoles with karyotypes corresponding to P. ridibundus karyotype. Thus diploid males most probably produced haploid gametes with P. ridibundus genome. We suggest that triploid hybrid frogs cannot reproduce independently from diploid hybrids. In studied population systems, diploid hybrid females are likely to be responsible for appearance of triploid hybrids as well as new diploid hybrids.
Gamete production patterns and mating systems in water frogs of the hybridogenetic Pelophylax esculentus complex in northeastern Ukraine
(Journal of Zoological Systematics and Evolutionary Research, 2016) Biriuk, O.V.; Shabanov, D.A.; Korshunov, A.V.; Borkin, L.J.; Lada, G.A.; Pasynkova, R.A.; Rosanov, J.M.; Litvinchuk, S.N.
Hybridization and polyploidy play an important role in animal speciation. European water frogs of the Pelophylax esculentus complex demonstrate unusual genetic phenomena associated with hybridization, clonality and polyploidy which presumably indicate an initial stage of reticulate speciation. The Seversky Donets River drainage in north-eastern Ukraine is inhabited by both sexes of the diploid and triploid hybrid P. esculentus and only one parental species Pelophylax ridibundus. Based on the presence of various types of hybrids, all populations studied can be divided into three geographical groups: I) P. ridibundus—P. esculentus without triploids; II) P. ridibundus—P. esculentus without diploid hybrids; and III) P. ridibundus—P. esculentus with a mixture of diploids and triploids. A study of gametogenesis revealed that diploid P. esculentus in populations of the ﬁrst type usually produced haploid gametes of P. ridibundus and a mixture of haploid gametes that carried one or another parental genome (hybrid amphispermy). In populations of the second type, hybrids are derived from crosses of P. ridibundus males with triploid hybrid females producing haploid eggs with a genome of P. lessonae. Therefore, we suggest that clonal genome duplication in these eggs might be the result of suppression of second polar body formation or extra precleavage endoreduplication. In populations of the third type, some diploid females can produce diploid gametes. Fertilization of these eggs with haploid sperm can result in triploid hybrids. Other hybrids here produce haploid gametes with one or another parental genome or their mixture giving rise to new diploid hybrids.
Inﬂuence of environmental conditions on the distribution of Central Asian green toads with three ploidy levels
(Journal of Zoological Systematics and Evolutionary Research, 2011) Litvinchuk, S.N.; Mazepa, G.; Pasynkova, R.A.; Saidov, A.; Satorov, T.; Chikin, Yu.; Shabanov, D.A.; Crottini, A.; Borkin, L.J.; Rosanov, J.M.; Stock, M.
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.
Inheritance of parental genomes by a hybrid form Rana “esculenta” (Amphibia, Ranidae)
(Russian Journal of Genetics, 2009) Morozov-Leonov, S.Yu.; Mezhzherin, S.V.; Nekrasova, O.D.; Shabanov, D.A.; Korshunov, A.V.; Krutyak, F.F.
In this study, quantitative analysis of paternal genome inheritance by a hybrid form Rana “esculenta” (= Rana esculenta L., 1758 × Rana ridibunda Pall., 1881) (Amphibia, Ranidae) was examined. The hybrid form examined was characterized by a polymodal mode of inheritance (genome of any of the parental species can be inherited). The absence of correlation between the proportion of normal gametes and either sex or ploidity of the producer was demonstrated. The gametes produced could be both haploid and diploid (hybrid or homozygous). The mechanism of alloploid reproduction is discussed.
Mass occurrence of polyploid green frogs (Rana esculenta complex) in Eastern Ukraine
(Russian Journal of Herpetology, 2004) Borkin, L.J.; Korshunov, A.V.; Lada, G.A.; Litvinchuk, S.N.; Rosanov, J.M.; Shabanov, D.A.; Zinenko, A.I.
Первое сообщение об обнаружении Северско-Донецкого центра разнообразия зеленых лягушек
Study of the bufadienolides of the skin secretion of green toads (Bufo viridis Laur, 1758)
(Pharmaceutical Chemistry Journal, 1995) Gella, I.M.; Shabanov, D.A.; Leont'ev, D.A.; Levin, M.G.; Shishkin, O.V.; Baumer, V.N.; Lakin, E.E.
The composition of the skin secretion of Bufo viridis toads, which inhabit the Kharkov region, has been studied in this work.
The ploidy and genetic structure of hybrid population of water frogs Pelophylax esculentus complex (Amphibia, Ranidae) of Ukraine fauna
(Cytology and Genetics, 2010) Mezhzherin, S.V.; Morozov-Leonov, S.Yu.; Rostovskaya, O.V.; Shabanov, D.A.; Sobolenko, L.Yu.
The complex study, including allozyme variability and cytometry of hybrid populations of green frogs Pelophylax esculentus (L., 1758) complex has confirmed that the only region of Ukraine where allodip loid are encountered frequently is the Severski Donets basin (9% of all hybrids). In other areas, only two poly ploidy hybrids (0.9%) and one probably autopolyploid individual of each parental species have been regis tered. According to allozyme specters, all three polyploidy hybrids from the Severski Donets basin were males and belonged to biotype P. esculentus (=lessonae) – 2 ridibundus, and their population in this region has halved during the past decade.
The study of three hemiclonal population systems Pelophylax esculentus complex from the Seversko-Donetskiy center of green frogs diversity
(Вісник Харківського національного університету імені В. Н. Каразіна. Серія «Біологія», 2014) Meleshko, O.V.; Korshunov, O.V.; Shabanov, D.A.
The structure of hemiclonal population systems (HPS) of Pelophylax esculentus complex from the Iskov pond (Gaydary village, Zmiyiv District), the Lower Dobritskiy pond (the region of Gomolsha river floodplain, Dobritskiy yar, the territory of the National Park “Gomolshanski lisy”) and from the pond near the village Zhovtneve (Vovchanskiy District, Kharkiv Region) was studied. All studied HPS were defined as REt-type. We observed the triploid hybrids number increasing in the HPS from the Iskov pond. The large part of triploid hybrids was found in the HPS of the Lower Dobritskiy pond. It was observed that all triploid hybrids from the pond near the village Zhovtneve were females. There was significant bond between the diploid erythrocytes size and sex of the frogs. It seems that triploids in this HPS are originating in other way compared to other HPS. There were two groups of females differ in body size which possibly corresponds to different ontogenetic strategies of green frog females. The males have a normal size distribution.