Effects of geographic distance, sea barriers and habitat on the genetic structure and diversity of all-hybrid water frog populations

Dg, Christiansen; Hu, Reyer

doi:10.1038/hdy.2010.37

Cited by 24 publications

(20 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As most primers amplified in only one of the two genomes (L or R, Table ), it was immediately obvious from the microsatellite profile whether an individual had a parental or hybrid genotype. With prior expectations of genome specificity from previous studies (Christiansen , ; Christiansen & Reyer , ), supported by field notes describing the supposed taxon of the individual based on morphological characters, L specificity and R specificity could be inferred for the majority of loci. The hybrid types were also clearly distinguishable from parental genotypes by their amplification patterns.…”

Section: Methodssupporting

confidence: 63%

Genetic diversity and distribution patterns of diploid and polyploid hybrid water frog populations (Pelophylax esculentus complex) across Europe

et al. 2015

View full text Add to dashboard Cite

Polyploidization is a rare yet sometimes successful way for animals to rapidly create geno- and phenotypes that may colonize new habitats and quickly adapt to environmental changes. In this study, we use water frogs of the Pelophylax esculentus complex, comprising two species (Pelophylax lessonae, genotype LL; Pelophylax ridibundus, RR) and various diploid (LR) and triploid (LLR, LRR) hybrid forms, summarized as P. esculentus, as a model for studying recent hybridization and polyploidization in the context of speciation. Specifically, we compared the geographic distribution and genetic diversity of diploid and triploid hybrids across Europe to understand their origin, maintenance and potential role in hybrid speciation. We found that different hybrid and parental genotypes are not evenly distributed across Europe. Rather, their genetic diversity is structured by latitude and longitude and the presence/absence of parental species but not of triploids. Highest genetic diversity was observed in central and eastern Europe, the lowest in the northwestern parts of Europe. This gradient can be explained by the decrease in genetic diversity during postglacial expansion from southeastern glacial refuge areas. Genealogical relationships calculated on the basis of microsatellite data clearly indicate that hybrids are of multiple origin and include a huge variety of parental genomes. Water frogs in mixed-ploidy populations without any parental species (i.e. all-hybrid populations) can be viewed as evolutionary units that may be on their way towards hybrid speciation. Maintenance of such all-hybrid populations requires a continuous exchange of genomes between diploids and triploids, but scenarios for alternative evolutionary trajectories are discussed.

show abstract

Section: Methodssupporting

confidence: 63%

Genetic diversity and distribution patterns of diploid and polyploid hybrid water frog populations (Pelophylax esculentus complex) across Europe

et al. 2015

View full text Add to dashboard Cite

show abstract

“…3 and Table S1). Microsatellite alleles with just a few base pairs difference are thus highly reliable for ploidy determination (Christiansen & Reyer 2011). With the large length difference of the L‐ and R ‐ specific band of SAI‐1, strong amplification bias towards the shorter allele squeezes the PHRs for all karyotypes together.…”

Section: Discussionmentioning

confidence: 99%

“…It is highly unlikely that one allele could mutate to the length of the other. With microsatellite alleles often having just a few repeats difference in between, such size‐homoplasy apparently arises relatively often in geographic areas with high allele diversity (Christiansen & Reyer 2011). Therefore, a reliable method for distinguishing both taxon and karyotype may consist of a combination of markers with large and small allele differences, as for example the present method with genotyping a few microsatellites.…”

Section: Discussionmentioning

confidence: 99%

“…Thirty‐eight of the Polish samples and all 53 samples from Lithuania and Latvia had been genotyped for 18 microsatellite loci, while the 53 samples from Sweden had been genotyped with nine diagnostic microsatellite markers (see Tables S2a,b, Supporting information for details on the microsatellite genotyping). The results of the Lithuanian and Latvian samples had been published in Christiansen & Reyer (2011).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

A simplified molecular method for distinguishing among species and ploidy levels in European water frogs (Pelophylax)

Hauswaldt

Höer

Ogielska

et al. 2012

Molecular Ecology Resources

View full text Add to dashboard Cite

Western Palearctic water frogs in the genus Pelophylax are a set of morphologically similar anuran species that form hybridogenetic complexes. Fully reliable identification of species and especially of hybrid ploidy depends on karyological and molecular methods. In central Europe, native water frog populations consist of the Pelophylax esculentus complex, that is, P. lessonae (LL), P. ridibundus (RR) and the hybrid form P. esculentus that can have different karyotypes (RL, LLR and RRL). We developed existing molecular methods further and propose a simple PCR method based on size-differences in the length of the serum albumin intron-1 and the RanaCR1, a non-LTR retrotransposon of the chicken repeat (CR) family. This PCR yields taxon-specific banding patterns that can easily be screened by standard agarose gel electrophoresis and correctly identify species in all of the 160 samples that had been identified to karyotype with other methods. To distinguish ploidy levels in LR, LLR and RRL specimens, we used the ratio of the peak heights of the larger (ridibundus specific) to the smaller (lessonae specific) bands of fluorescently labelled PCR products resolved on a capillary DNA sequencer and obtained a correct assignment of the karyotype in 93% of cases. Our new method will cut down time and expenses drastically for a reliable identification of water frogs of the P. esculentus complex and potentially for identification of other hybridogenetic complexes and/or taxa, and it even serves as a good indicator of the ploidy status of hybrid individuals.

show abstract

“…The purified DNA was subjected to PCR runs with four primer mixes involving a total of 18 microsatellites primer pairs (Table ). Details on PCR protocols are given by Christiansen () and Christiansen & Reyer (, ). PCR products were run for fragment length analysis on an ABI 3730 Avant capillary sequencer with internal size standard (GeneScan‐500 LIZ), and the alleles were scored with the Genemapper software v3.7 (Applied Biosystems, Zug, Switzerland).…”

Section: Methodsmentioning

confidence: 99%

Genotype‐temperature interactions on larval performance shape population structure in hybridogenetic water frogs (Pelophylax esculentuscomplex)

2013

View full text Add to dashboard Cite

Summary 1.The evolutionary potential and ecological importance of interspecific hybrids continues to be a controversial issue. Traditionally, hybridization -often associated with polyploidy and clonal reproduction -was considered an important mechanism for speciation in plants, but not in animals. More recently, investigations have shifted to the question: Under which genetic and ecological conditions do hybrid taxa and different ploidies arise and succeed, and when and where do they fail? Finding answers to this question is aggravated by the fact that suitable taxa for such studies are often far apart on the phylogenetic tree. Hence, results are influenced by many confounding variables. 2. In this study, we reduce this problem by investigating the fitness within a complex of three closely related water frog taxa consisting of the two sexually reproducing parental species Pelophylax lessonae (genotype LL) and P. ridibundus (RR) plus their interspecific hybrid P. esculentus which comes in three ploidy types (LR, LLR and LRR), as well as with sexual and hemiclonal reproduction. Offspring of all five genotypes were produced by artificially crossing adults sampled from populations in Slovakia, Germany and Switzerland. This created genetic variation. They were then raised at two temperature levels: 18 and 24°C. This created ecological variation. Larval performance under the two temperature regimes was analysed with respect to three fitness-related parameters: survival rate, days to metamorphosis and weight at tail resorption. 3. Survival rate was significantly higher for offspring of the three hybrid types (LR, LLR and LRR) compared with those of the parental species (LL, RR), at both rearing temperatures. For days to metamorphosis and weight at metamorphosis, we found an interaction between offspring type and temperature. In both cases, performance of hybrid and parental offspring did not differ at 24°C, but at 18°C hybrids metamorphosed faster and at a lower weight than parentals. 4. We discuss these results in relation to those from other studies and conclude that under cold conditions hybrids (especially the two triploid types) have higher fitness than both parental species. This genotype 9 environment interaction could be one reason why all-hybrid populations mainly occur at the cooler northern range of the water frog distribution.

show abstract

Effects of geographic distance, sea barriers and habitat on the genetic structure and diversity of all-hybrid water frog populations

Cited by 24 publications

References 34 publications

Genetic diversity and distribution patterns of diploid and polyploid hybrid water frog populations (Pelophylax esculentus complex) across Europe

Genetic diversity and distribution patterns of diploid and polyploid hybrid water frog populations (Pelophylax esculentus complex) across Europe

A simplified molecular method for distinguishing among species and ploidy levels in European water frogs (Pelophylax)

Genotype‐temperature interactions on larval performance shape population structure in hybridogenetic water frogs (Pelophylax esculentuscomplex)

Contact Info

Product

Resources

About