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1.
The highly repetitive Rana/Pol III family consists of short, tandemly arrayed sequences, scattered throughout the genomes of Palearctic green water frogs. The repeat unit is about 250 bp in length and is a composite element: it contains a SINE-like retroposon with a tRNA structure, flanked by two short direct repeats, and the occurrence of two internal repeats gives evidence that an additional transposition event may have inserted a segment within the already transposed element. Rana/Pol III family is present in the genomes of Rana lessonae, R. ridibunda, and their hybrid form R. esculenta, as well as in R. shqiperica. R. epeirotica, R. cretensis, and the Italian taxon. These sequences are also present in the Iberian R. perezi, although less abundant, but appear to be lacking in the north African species R. saharica. The distribution of Rana/Pol III in the genomes of Palearctic green frogs is in agreement with the phyletic history based on genetic data. The evolutionary pattern proposed for the genus Rana enables us to suppose that the hybridogenetic mechanism is one of the factors accounting for the possible horizontal transfer of Rana/Pol III elements from the central-north Europe species to R. perezi.  相似文献   

2.
The variable microsatellite repeat BM224 has been discovered in the genomes of eight species of green frogs (Rana ridibunda, R. cf bedriagae, R. cretensis, R. esculenta, R. lessonae, R. shquiperica, R. saharica, R. nigromaculata). Earlier, this repeat had been observed in members of the genus Bufo. In this paper, a possibility of usage of this genetic marker for species identification is discussed.  相似文献   

3.
The variable microsatellite repeat BM224 has been revealed in the genomes of eight species of green frogs (Rana ridibunda, R. cf. bedriagae, R. cretensis, R. esculenta, R. lessonae, R. shquiperica, R. saharica, R. nigromaculata). Previously, this repeat was observed in members of the genus Bufo. In this paper, the possibility of using this genetic marker for species identification is discussed.  相似文献   

4.
Phylogenetic relationships in the western fraction of Rana (Pelophylax) have not been resolved till now, even though several works have been devoted to the subject. Here, we infer phylogenetic relationships among the species distributed in the area of the Eastern Mediterranean, comparing partial mitochondrial DNA sequences for the cytochrome b and 16S rRNA genes. The obtained molecular data clearly indicate that Western Palearctic water frogs underwent a basal radiation into at least 3 major lineages (the perezi, the lessonae, and the rindibunda/bedriagae lineages) advocating an upper Miocene speciation. Moreover, we consider that within the rindibunda/bedriagae lineage, R. (P.) ridibunda, R. (P.) epeirotica, R. (P.) cretensis, R. (P.) bedriagae, R. (P.) cerigensis and R. (P.) kurtmuelleri were differentiated from a common ancestor through a series of vicariant and dispersal events, during the last approximately 5Mya, even though the specific rank of some taxa may be questionable, such as R. cerigensis in respect with R. bedriagae and R. kurtmuelleri in respect with R. ridibunda.  相似文献   

5.
Six structural and temporal features of the mating calls of pool frogs recorded at eight localities in Italy, Germany, Yugoslavia and Albania were compared with those of the calls of topotypical Rana lessonae in northern Italy. All populations shared three out of six characters studied: call duration, intercall interval and call period. The pool frogs of three localities in peninsular Italy significantly differed in three characters from those of the other six localities, including the northern Italian one: pulses per pulse group, pulse groups per call, and pulse groups per second. This study demonstrates the existence of Rana bergeri , a pool frog species different from R. lessonae in peninsular Italy, but does not support the species status of the chemotaxonomically established R. shqiperica , which is considered as a synonym of R. lessonae .  相似文献   

6.
Temporal characteristics of advertisement calls of water frogs of 10 localities in Turkey, Syria, Israel and Egypt were compared with those of Rana ridibunda in Kazakhstan, Armenia and Greece (Thrace) as reference populations. These study sites include the type localities of R. ridibunda , R. r. caralitana , R. esculenta var. bedriagae und R. levantina . The temperature-dependent as well as the temperature-independent call parameters clearly revealed two species. R. ridibunda is represented by the three reference populations and, in addition, a population in central Turkey. The other populations (in Turkey, Syria, Israel and Egypt) represent R. bedriagae . R. bedriagae is the oldest available name for water frogs of these regions and was given priority over R. r. caralitana and R. levantina .  相似文献   

7.
Eight morphometric features of water frogs of 14 localities in Turkey, Syria, Jordan and Israel were compared with those of Rana ridibunda in Kazakhstan, Armenia and Greece (Thrace). These study sites include the type localities of R. ridibunda , R. r. caralitana , R. esculenta var. bedriagae and R. levantina . Multivariate comparisons (principal-component analysis, discriminant analysis) based on the log10-transformed variables demonstrate that the data set includes only two taxa that differ significantly in size and shape. By applying a morphospecies criterion, R. ridibunda is represented exclusively by the three reference populations, whereas all other populations (in Turkey, Syria, Jordan and Israel) represent the same species , R. bedriagae .  相似文献   

8.
Survival and some physiological responses to freezing were investigated in three European water frogs (Rana lessonae, Rana ridibunda, and their hybridogen Rana esculenta). The three species exhibited different survival times during freezing (from 10 h for R. lessonae to 20 h for R. ridibunda). The time courses of percent water frozen were similar; however, because of the huge differences in body mass among species (from 10 g for Rana lessonae to nearly 100 g for Rana ridibunda), the ice mass accumulation rate varied markedly (from 0.75 +/- 0.12 to 1.43 +/- 0.11 g ice/h, respectively) and was lowest in the terrestrial hibernator Rana lessonae. The hybrid Rana esculenta exhibited an intermediate response between the two parental species; furthermore, within-species correlation existed between body mass and ice mass accumulation rates, suggesting the occurrence of subpopulations in this species (0.84 +/- 0.08 g ice/h for small R. esculenta and 1.78 +/- 0.09 g ice/h for large ones). Biochemical analyses showed accumulation of blood glucose and lactate, liver glucose (originating from glycogen), and liver alanine in Rana lessonae and Rana esculenta but not in Rana ridibunda in response to freezing. The variation of freeze tolerance between these three closely related species could bring understanding to the physiological processes involved in the evolution of freeze tolerance in vertebrates.  相似文献   

9.
Interspecies transfer of mitochondrial (mt) DNA is a common phenomenon in plants, invertebrates and vertebrates, normally linked with hybridization of closely related species in zones of sympatry or parapatry. In central Europe, in an area north of 48 degrees N latitude and between 8 degrees and 22 degrees E longitude, western Palaearctic water frogs show massive unidirectional introgression of mtDNA: 33.7% of 407 Rana ridibunda possessed mtDNA specific for Rana lessonae. By contrast, no R. lessonae with R. ridibunda mtDNA was observed. That R. ridibunda with introgressed mitochondrial genomes were found exclusively within the range of the hybrid Rana esculenta and that most hybrids had lessonae mtDNA (90.4% of 335 individuals investigated) is evidence that R. esculenta serves as a vehicle for transfer of lessonae mtDNA into R. ridibunda. Such introgression has occurred several times independently. The abundance and wide distribution of individuals with introgressed mitochondrial genomes show that R. lessonae mt genomes work successfully in a R. ridibunda chromosomal background despite their high sequence divergence from R. ridibunda mtDNAs (14.2-15.2% in the ND2/ND3 genes). Greater effectiveness of enzymes encoded by R. lessonae mtDNA may be advantageous to individuals of R. ridibunda and probably R. esculenta in the northern parts of their ranges.  相似文献   

10.
In Anurans, the specific mate recognition system (SMRS), which contributes to prezygotic isolation, is mainly based on morphological and call features. This is why such criteria are used by zoologists for taxonomic identification. In hybridogenetic water frogs (Rana ridibunda, R. lessonae, R. perezi, R. kl. grafi and R. kl. esculenta), hybridization opens up the question of the efficiency of these criteria for taxon identification and of the specific recognition system in this context. Variation in both morphological and call features revealed both significant mean differences among taxa but also large overlapping among individuals belonging to different taxa. Thus, using call or morphometrical features in order to identify water frogs may be hazardous. Moreover, species differ poorly in their specific mate recognition system, facilitating hybridization events, and therefore suggesting that postzygotic mechanisms may be prevalent over prezygotic mechanisms.  相似文献   

11.
1. Water and electrolyte reabsorption of the urinary bladder epithelia has been studied in intact, fully hydrated frogs (Rana temporaria, R. lessonae, R. ridibunda). 2. The rates of water reabsorption were lower in frogs on wet soil than in those on dry soil and related to the degree of terrestrialism: R. temporaria greater than R. lessonae greater than R. ridibunda. 3. Samples of urine stored up to 24 hr within the urinary bladder were analysed for osmolality and the concentration of urea, ammonia, sodium, potassium, magnesium and calcium. 4. Selective reabsorption of sodium was detected in all species, that of calcium only in R. ridibunda. The efficiency of electrolyte reabsorption was also related to the degree of terrestrialism. 5. In conclusion, in fully hydrated frogs reabsorption by the bladder epithelia contributes significantly to the water and electrolyte conservation.  相似文献   

12.
Mitotic chromosomes of the European water frogs Rana ridibunda and Rana lessonae, the parental species of Rana esculenta, differ significantly in their centromeric regions: when C-banded or when made fluorescent, the centromeres of R. ridibunda (and of ridibunda chromosomes in R. esculenta) are visible as a conspicuous dark granule or as a conspicuous fluorescent spot; the centromeres of R. lessonae (and of the lessonae chromosomes in R. esculenta) are inconspicuous or not fluorescent. Lampbrush chromosomes of these three taxa are described in detail for the first time; those of R. ridibunda and R. lessonae differ significantly in morphostructural characters such as conspicuousness of centromeres and number, form, and location of giant loops as well as in chiasma frequency. Chromosomes of the two parental species can thus be distinguished when present in lampbrush complements of hybrids. Reproduction in both sexes of natural R. esculenta lineages is hemiclonal: only the unrecombined genome of one parental species, usually R. ridibunda, is transmitted to haploid gametes (hybridogenesis). In 18 hybrids from natural populations of Poland, somatic tissues had allodiploid complements with chromosomes from each parental species. In contrast, spermatocytes I of five males and oocytes I of seven of eight females (221 of 222 oocytes) were autodiploid and contained only R. ridibunda chromosomes that formed n bivalents. These 12 hybrids thus were hybridogenetic. A single female hybrid had oocytes I (33 of 34) with genomes of both parental species; they showed various disturbances including tetraploidy, reduced number of chiasmata, and incomplete synapsis resulting in univalents. This individual thus was not hybridogenetic. The irregular lampbrush patterns indicate that such hybrids will have severely reduced fertility and most of their successful gametes will result in allotriploid progeny.  相似文献   

13.
Gametogenesis of intergroup hybrids of hemiclonal frogs   总被引:1,自引:0,他引:1  
European water frog hybrids Rana esculenta (R. ridibundaxR. lessonae) reproduce hemiclonally, by hybridogenesis: in the germ line they exclude the genome of one parental species and produce haploid gametes with an unrecombined genome of the other parental species. In the widespread L-E population system, both sexes of hybrids (E) coexist with R. lessonae (L). They exclude the lessonae genome and produce ridibunda gametes. In the R-E system, hybrid males coexist with R. ridibunda (R); they exclude either their ridibunda or their lessonae genome and produce sperm with a lessonae or with a ridibunda genome or a mixture of both kinds of sperm. We examined 13 male offspring, 12 of which were from crosses between L-E system and R-E system frogs. All were somatically hybrid. With one exception, they excluded the lessonae genome in the germ line and subsequently endoreduplicated the ridibunda genome. Spermatogonial metaphases contained a haploid or a diploid number of ridibunda chromosomes, identified through in situ hybridization to a satellite DNA marker, and by spermatocyte I metaphases containing a haploid number of ridibunda bivalents. The exception, an F1 hybrid between L-E system R. lessonae and R-E system R. ridibunda, was not hybridogenetic, showed no genome exclusion, and evidenced a disturbed gametogenesis resulting from the combination of two heterospecific genomes. None of the hybridogenetic hybrids showed any cell lines excluding the ridibunda genome, the pattern most frequent in hybrids of the R-E system, unique to that system, and essential for its persistence. A particular combination of R-E system lessonae and R-E system ridibunda genomes seems necessary to induce the R-E system type of hemiclonal gametogenesis.  相似文献   

14.
Water frogs are involved in several hybridogenetic complexes. However, investigations in Southern and Western France produced evidence of new hybridization events between R. lessonae and R. perezi (some new hybrids tadpoles were discovered), and the existence of new assemblages [R–G, L–P, R–P, P–R–G: (R,  ridibunda; G,  grafi; L, lessonae; P,  perezi )]. In respect to hybridogenesis, these assemblages offer opportunities for both primary and secondary hybridizations. Such peculiarities may be explained either by introductions or by relic populations and may influence water frog evolution.  相似文献   

15.
In this study it has been proved by PAGE of serum proteins that all the three members of the Rana esculenta complex occur in the Kis-Balaton Nature Reserve (Hungary). On the basis of the LDH isoenzyme pattern which is characteristic in green frogs we could distinguish all three variations of R. ridibunda and R. lessonae and one type of R. esculenta. The mobility of serum albumins on SDS-PAGE implies that the R. esculenta comes from hybridization of the two other species. The PAGE methods provide a reliable basis for the rapid taxonomic identification of both adults and immature speciments of the three forms of frogs.  相似文献   

16.
The ecological success of introduced species in their new environments is difficult to predict. Recently, the water frog species Rana ridibunda has raised interest, as different genetic lineages were introduced to various European countries. The aim of the present study was to analyze the potential invasiveness of R. ridibunda and assess the risk of replacement for indigenous water frog species. The investigation of over 700 water frogs from 22 locations in southern France and four locations in Spain shows that the competition with indigenous species is mainly limited to a particular habitat type, characterized by high-oxygen and low-salinity freshwater. The competitive strength of R. ridibunda may be related to a higher growth rate and longevity as compared to the indigenous species R. grafi and R. perezi. Our data suggest that R. ridibunda is a risk to the diversity of indigenous water frog assemblages in France. Future monitoring needs to clarify the distribution of R. ridibunda, its ecological niche, and the risk status for indigenous water frog species.  相似文献   

17.
Patterns of advertisement call were investigated in two genetically distinct water frog lineages ( Rana kl esculenta, Rana. kl grafi ), which were identified by starch gel electrophoresis – the aim being to determinate the role of vocalization in the hybridogenetic process. Both hybrids displayed major modifications from the basic structure of the Rana ridibunda call. In Rana kl grafi , the call structure tended to correspond to that of Rana perezi in most of the studied parameters (frequency, duration, number of pulses) whereas the call of Rana kl esculenta tended to resemble that of Rana lessonae . The ascendant hierarchical classification clearly revealed such a convergence toward parental species and accounted for a divergence between hybrids. Changes in call patterns might result from both the expression of the non- ridibunda genome and the sexual selective pressure through female mate choice. Only few non- ridibunda females exhibited a preference for hybrid calls which, however, allowed some hybridogenetic males to obtain successful mates. Thus, hybridogenesis induced character convergence in courtship signal with the non- ridibunda species in hybrid zones. In any case, these changes in the courtship signal favoured the particular hybridogenetic process, which constitutes a quasi-parasitism of the non- ridibunda genome.  相似文献   

18.
European water frog hybrids Rana esculenta reproduce hemiclonally, by hybridogenesis: In the germ line they exclude the genome of the parental species Rana lessonae and produce haploid, unrecombined gametes with a genome of the parental species Rana ridibunda . These hybrids coexist with and depend as sexual parasites on the host parental species R. lessonae (the L-E population system); matings with R. lessonae restore somatic hybridity in each generation of R. esculenta . We investigated 15 L-E system populations in northern Switzerland, which is outside R. ridibunda 's native range. Frequency of hybrids in samples varied from 8% in marsh ponds to 100% in gravel pits and forest ponds. Clonal diversity (variation among R. ridibunda genomes of hybrids), detected by six protein electrophoretic marker loci, revealed a total of eight hemiclones and locally ranged from uniclonal populations in southern parts of the survey region to six coexisting hemiclones in the north. All alleles distinguishing hemiclones occur commonly in the nearest native R. ridibunda populations of east-central Europe; the most probable source of clonal diversity in our samples is multiple clone formation by primary hybridizations in the sympatry area of R. ridibunda and R. lessonae and subsequent dispersal of hemiclonal lineages. A positive correlation between amount of clonal diversity and hybrid frequency, predicted by the Frozen Niche Variation (FNV) model (each hemiclone is characterized by a relatively narrow niche, coexistence is possible through niche partitioning), was not found; this contrasts with hemiclonally reproducing fish hybrids ( Poeciliopsis ). Historical factors, such as availability of different colonizing hemiclones may be strong enough to override the signal from operation of the FNV.  相似文献   

19.
mtDNA of the hybridogenetic hybrid frog Rana esculenta from Switzerland, Austria, and Poland was compared to mtDNA of the parental species R. ridibunda and R. lessonae using electrophoretic analysis of restriction enzyme fragments. Two mtDNA phenotypes, with 3.4% sequence divergence, are present in R. lessonae: type C is found in Poland, and type D is found in Switzerland. Rana ridibunda from Poland has either of two mtDNA phenotypes: type A is the typical ridibunda mtDNA, and type B is a lessonae mitochondrial genome, introgressed into R. ridibunda, that differs from type C mtDNA of R. lessonae by only 0.3%. Each of the three lessonae genomes differs from A, the typical ridibunda mtDNA, by approximately 8%. All four types of mtDNA (A and B of R. ridibunda, C and D of R. lessonae) are found in R. esculenta. Of 62 R. esculenta from Poland, 58 had type C, three had type A, and one had type B mtDNA. All nine R. esculenta from Switzerland had type D mtDNA. All three R. esculenta from Austria, from a population in which males of R. esculenta are rare, had ridibunda mtDNA, two having type B and one having type A. Both field observations and studies of mating preference indicate that the primary hybridizations that produce R. esculenta are between R. ridibunda females and R. lessonae males; thereafter, R. esculenta lineages are usually maintained by matings of R. esculenta females with R. lessonae males. The presence of ridibunda mtDNA in the three R. esculenta sampled from Austria, its occasional presence in R. esculenta populations in Poland, and its absence from R. esculenta in Switzerland support both the direction of the original hybridization and the rarity of formation of new R. esculenta lineages. The preponderance of R. esculenta individuals with lessonae mtDNA in our samples from central Europe suggests that most lineages have gone through at least one mating between an R. lessonae female and an R. esculenta male. This reveals a greater reproductive role for R. esculenta males than their partial sterility and infrequent matings would suggest.   相似文献   

20.
1. Clonally reproducing species are often assumed to lack sufficient genetic variability to evolve specific local adaptations to cope with environmental perturbation and competition from sexual species. Yet, many asexuals are extremely successful judged by abundance and wide range, suggesting high competitive abilities in resource exploitation.
2. In this study, food use and its effects on larval growth in a water frog system consisting of the two parental sexual species, Rana lessonae (Camerano 1882) and Rana ridibunda (Pallas 1771), and three different coexisting hemiclones of their hybrid, Rana esculenta (Linnaeus 1758) were investigated.
3. R. esculenta tadpoles spent 18·6% more time feeding than did tadpoles of either parental species, but feeding time was not affected by interspecific mixture.
4. R. esculenta tadpoles consumed 50·8% more food over the whole test period than did tadpoles of the two parental species.
5. R. esculenta tadpoles exhibited higher growth rates than did tadpoles of either parental species.
6. R. lessonae tadpoles had the highest and R . ridibunda tadpoles the lowest growth efficiencies with the R. esculenta tadpoles ranging between the two parentals.
7. The results obtained indicate that hemiclonal hybridogenetic R . esculenta tadpoles display significant phenotypic variation among coexisting hemiclones as well as out-perform tadpoles of the parental sexual species R. lessonae and R . ridibunda. The primary mechanism for success of the hybrid tadpoles is probably behavioural, through increased feeding time and food consumption, and not physiological via growth efficiency.  相似文献   

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