Additional file 1: Table S1. of Mutual maintenance of di- and triploid Pelophylax esculentus hybrids in R-E systems: results from artificial crossings experiments

List of studied European water frogs from the R-E systems in Eastern Ukraine. (XLSX 18 kb

Suggested additional mechanisms of oogenesis in two triploid frogs with RRL genotype and one diploid hybrid frog.

<p>(a) During oogenesis of one triploid frog with RRL genotype neither elimination nor endoreplication occurred to form oocytes with 39 univalents (at the top), endoreplication of all genomes took place to form oocytes with 39 bivalents (in the middle), individual chromosomes from L genome (blue) were lost to form oocytes with aneuploid chromosomal sets (at the bottom). (b) During oogenesis of another triploid frog with RRL genotype elimination of L genome (blue) occurred to form oocytes with 13 bivalents (at the top), premeiotic elimination and endoreplication were absent to form oocytes with 39 univalents (in the middle), endoreplication of all genomes took place to form oocytes with 39 bivalents (at the bottom). (c) During oogenesis of one diploid hybrid frog L genome (blue) was eliminated in all observed oocytes. One round of R genome (orange) endoreplication occurred but bivalents formation was incomplete to form oocytes with both univalents and bivalents (at the top). Two rounds of endoreplication of R genome took place to form oocytes 26 bivalents (in the middle). One round of R genome endoreplication occurred but bivalents could not form that led to formation of oocytes with 26 univalents (at the bottom).</p

Suggested mechanisms of oogenesis typical for triploid hybrid frogs with RRL genotype and diploid hybrid frogs.

<p>(a) During oogenesis of the majority of triploid hybrids with RRL genotype from studied population systems of R-E type, L genome (blue) was eliminated while two remaining R genomes (brown and orange) without endoreplication formed 13 bivalents. (b) In oogenesis of the majority of diploid hybrids with RL genotype from studied population systems of R-E type, L genome (blue) was eliminated and the remaining R genome (orange) was endoreplicated to form 13 bivalents.</p

Interstitial (TTAGGG)_n repeat sites mapping allows to identify parental chromosomes in oocytes of hybrid frogs.

<p>(a-c) FISH mapping of (TTAGGG)_n repeat on metaphase chromosomes of <i>P</i>. <i>lessonae</i> (a, a`), <i>P</i>. <i>ridibundus</i> (b), and diploid <i>P</i>. <i>esculentus</i> (c). One or two interstitial (TTAGGG)<sub>n</sub> repeat sites distinguish parental NOR-bearing chromosomes H (arrows). Asterisks indicate enlarged fragment with two NOR-bearing chromosomes of <i>P</i>. <i>lessonae</i>. Arrows indicate interstitial (TTAGGG)<sub>n</sub> repeat sites. (d1–f1`) Lampbrush chromosomes from oocytes of triploid hybrid frogs with RRL (d1–d6`) and LLR (e1–f1`) genotypes. FISH mapping of (TTAGGG)_n repeat revealed lampbrush chromosome H corresponding to <i>P</i>. <i>ridibundus</i> (d6) or <i>P</i>. <i>lessonae</i> (e1) LBC H. Interstitial (TTAGGG)_n repeat sites are shown by square brackets. Lampbrush chromosomes corresponding to <i>P</i>. <i>ridibundus</i> LBC F (d1,d1`), G (d2,d2`), D (d3,d3`), I (d4,d4`), B (d5,d5`), and <i>P</i>. <i>lessonae</i> LBC B (e2,b2`), F (e3,b3`), L (f1,f1`) are shown. Chromosomes on micrographs (d1–d6`) were taken from the full lampbrush chromosome set represented on <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0123304#pone.0123304.g001" target="_blank">Fig 1a,a`</a>. Chromosomes on micrographs (e1–e3`) were taken from the from the full lampbrush chromosome set represented on <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0123304#pone.0123304.g001" target="_blank">Fig 1c,c`</a>. Various marker structures are shown by arrows. Chromosomes were counterstained with DAPI. Corresponding phase-contrast micrographs are shown (d1`,d2`,d3`,d4`,d5`,d6`,e1`,e2`,e3`,f1`). Arrowheads indicate centromeres. Scale bars = 10 μm for all panels except a`, where scale bar = 2 μm.</p

L-genome phylogeny (input)

Data input for L-genome phylogeny in Fig.

Genetic structure within the R and L genome

Genetic differentiation within the R and L genome of water frogs of the Pelophylax esculentus complex, according to Bayesian analyses implemented in the program STRUCTURE. The proportion of membership (parameter q according to Pritchard et al. 2000) of each individual in each of the two (R genome) and four (L genome) inferred clusters is shown

Microsatellite markers

This Table lists the alleles found in each sampled individual (specified by ID numbers) on the Basis of six microsatellite marker

R-genome phylogeny (input)

Data input for R-Genome phylogeny in Fig.

Samples for microsatellite and mt DNA analysis

The Table summarizes which samples have been analyzed with microsatellites and/or mtDNA sequencing. Given are ID numbers, names and coordinates of samples sites an genotypes of frog

Origin and number of frogs used for mtDNA analysis

Populations, geographic coordinates and sample sizes of samples used for mtDNA analysis. The column “Microsat No.*” refers to the numbering of populations in Table S1 (new), where only populations used in microsatellite analyses are listed. Types of mtDNA are abbreviated as follows: les = lessonae-type, rid = ridibundus-type, ber = bergeri-type, cf. bed = cf. bedriagae-type