DOI: 10.5061/dryad.7nt8f
title: Data from: Hybrid asexuality as a primary postzygotic barrier between nascent species: on the interconnection between asexuality, hybridization and speciation

description: Although sexual reproduction is ubiquitous throughout nature, the
 molecular machinery behind it has been repeatedly disrupted during
 evolution, leading to the emergence of asexual lineages in all eukaryotic
 phyla. Despite intensive research, little is known about what causes the
 switch from sexual reproduction to asexuality. Interspecific hybridization
 is one of the candidate explanations but the reasons for the apparent
 association between hybridization and asexuality remain unclear. In this
 study we combined cross-breeding experiments with population genetic and
 phylogenomic approaches to reveal the history of speciation and asexuality
 evolution in European spined loaches (Cobitis). Contemporary species
 readily hybridize in hybrid zones, but produce infertile males and fertile
 but clonally reproducing females that cannot mediate introgressions.
 However, our analysis of exome data indicates that intensive gene flow
 between species has occurred in the past. Crossings among species with
 various genetic distances showed that, while distantly related species
 produced asexual females and sterile males, closely related species
 produce sexually reproducing hybrids of both sexes. Our results suggest
 that hybridization leads to sexual hybrids at the initial stages of
 speciation, but as the species diverge further, the gradual accumulation
 of reproductive incompatibilities between species could distort their
 gametogenesis towards asexuality. Interestingly, comparative analysis of
 published data revealed that hybrid asexuality generally evolves at lower
 genetic divergences than hybrid sterility or inviability. Given that
 hybrid asexuality effectively restricts gene flow, it may establish a
 primary reproductive barrier earlier during diversification than other
 ‘classical’ forms of postzygotic incompatibilities. Hybrid asexuality may
 thus indirectly contribute to the speciation process.
description: RNAseq_1G736HC302.RL5.sff.gzRNAseq_2G736HC302.RL8.sff.gzRNAseq_3IFMUJ8101.RL4.sff.gzRNAseq_4IFMUJ8101.RL5.sff.gzRNAseq_5IFMUJ8102.RL6.sff.gzRNAseq_6IFMUJ8102.RL10.sff.gzRNAseq_7IGASIBU01.RL5.sff.gzSeqCap_1.zipTo extract the contents of netrimovane_SeqCap.zip, first concatenate the parts 001 through 020 -- On a Unix or Linux machine, you may use the "cat" command as $ cat netrimovane* &gt; netrimovane_SeqCap.zip -- On a Windows machine, you may use the copy command, or a software such as HJSplit.netrimovane_SeqCap.zip.001SeqCap_2.zipnetrimovane_SeqCap.zip.002SeqCap_3.zipnetrimovane_SeqCap.zip.003SeqCap_4.zipnetrimovane_SeqCap.zip.004SeqCap_5.zipnetrimovane_SeqCap.zip.005SeqCap_6.zipnetrimovane_SeqCap.zip.006SeqCap_7.zipnetrimovane_SeqCap.zip.007SeqCap_8.zipnetrimovane_SeqCap.zip.008SeqCap_9.zipnetrimovane_SeqCap.zip.009SeqCap_10.zipnetrimovane_SeqCap.zip.010SeqCap_11.zipnetrimovane_SeqCap.zip.011SeqCap_12.zipnetrimovane_SeqCap.zip.012SeqCap_13.zipnetrimovane_SeqCap.zip.013SeqCap_14.zipnetrimovane_SeqCap.zip.014SeqCap_15.zipnetrimovane_SeqCap.zip.015SeqCap_16.zipnetrimovane_SeqCap.zip.016SeqCap_17.zipnetrimovane_SeqCap.zip.017SeqCap_18.zipnetrimovane_SeqCap.zip.018SeqCap_19.zipnetrimovane_SeqCap.zip.019SeqCap_20.zipnetrimovane_SeqCap.zip.020Four reference samples for exome capture and SNP calling_1.zipTo extract the contents of 'Four reference samples for exome capture and SNP calling_1.zip', first concatenate the parts 001 through 006 -- On a Unix or Linux machine, you may use the "cat" command as $ cat Four* &gt; Four_reference_samples_for_exome_capture_and_SNP_calling.zip -- On a Windows machine, you may use the copy command, or a software such as HJSplit.Four reference samples for exome capture and SNP calling.zip.001Four reference samples for exome capture and SNP calling_2.zipFour reference samples for exome capture and SNP calling.zip.002Four reference samples for exome capture and SNP calling_3.zipFour reference samples for exome capture and SNP calling.zip.003Four reference samples for exome capture and SNP calling_4.zipFour reference samples for exome capture and SNP calling.zip.004Four reference samples for exome capture and SNP calling_5.zipFour reference samples for exome capture and SNP calling.zip.005Four reference samples for exome capture and SNP calling_6.zipFour reference samples for exome capture and SNP calling.zip.006README_Description of original rna-seq and exome capture sequence data filesTable S1. Locality information from the Danube River hybrid zoneTable S1.docxAppendix S2. SNP datasetEvery contig is represented by 18 lines, with two lines per individual in standard fasta format. Header line of each sequence contains: sampleID_genotype_contigID. Individuals' genotypes are indicated by letters as follows: LL, C. paludica; PP, C. pontica; EE, C. elongatoides; TT, C. taenia; NN, C. tanaitica. Variant positions are expressed using IUPAC notation and invariant positions are excluded.Appendix S2.txtTable S3. Summary of the coalescent modelsTable S3.docxAppendix S4. Summary of genetic divergences of fish species producing asexual hybridsAppendix S4.docxTable S5. Microsatellite allelic profiles of parents and their progeny within crossing experimentsTable S5.xlsxTable S6. Oocyte analysisFor each female we indicate her biotype, origin, allozyme profile and the number of analyzed eggs.Table S6.xlsxTable S7. Microsatellite markers and cytochrome b gene haplotypesThis Table lists the alleles found in each sampled individual (specified by a respective ID number) on the basis of eight microsatellite markers. The cytochrome b gene haplotype is also specified.Table S7.xlsxTable S8. Summary statistics of microsatellite DNA analysis for three taxa based on eight lociTable S8.xlsxTable S9. SNP statisticsSummary statistics for within-species and between-species genetic distances.Table S9.xlsx