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Data from: Variable outcomes of hybridization between declining Alosa alosa and Alosa fallax

Cite this dataset

Lepais, Olivier et al. (2019). Data from: Variable outcomes of hybridization between declining Alosa alosa and Alosa fallax [Dataset]. Dryad.


Hybridization dynamics between co-occurring species in environments where human-mediated changes take place is important to quantify for furthering our understanding of human impacts on species evolution and for informing management. The allis shad Alosa alosa (Linnaeus, 1758) and twaite shad Alosa fallax (Lacépède, 1803), two clupeids sister species, have been severely impacted by human activities across Europe. The shrinkage of A. alosa distribution range along with the decline of the remaining populations’ abundance threaten its persistence. The main objective was to evaluate the extent of hybridization and introgression between those interacting species. We developed a set of 77 species-specific SNP loci that allowed a better resolution than morphological traits as they enabled the detection of hybrids up to the third generation. Variable rates of contemporary hybridization and introgression patterns were detected in 12 studied sites across the French Atlantic coast. Mitochondrial markers revealed a cyto-nuclear discordance almost invariably involving A. alosa individuals with an A. fallax mitochondrial DNA and provided evidence of historical asymmetric introgression. Overall, contemporary and historical introgression revealed by nuclear and mitochondrial markers strongly suggest that a transfer of genes occurs from A. fallax towards A. alosa genome since at least four generations. Moreover, the outcomes of introgression greatly depend on the catchments where local processes are thought to occur. Undoubtedly, interspecific interaction and gene flow should not be overlooked when considering the management of those species.

Usage notes

Data from: Taillebois et al. "Variable outcomes of hybridization between declining Alosa alosa and Alosa fallax" Evolutionary Application 2019

Sheets description:

- MassARRAY_Primers: Primer sequences for the MassARRAY Agena Bioscience SNP genotyping plateform ; genotyping analysis available at the Genome Transcriptome Facility of Bordeaux (

- GenotypicClasses_3Gen-NewHybrid: The genotypic classes expected for three generations hybridization used for New Hybrid assignment

- SNP-MitoHaplo-Assignement_data: The SNP genotype table and mitochondrial sequences and individual metadata including sampling localities, gill raker counts, Structure and NewHybrid assignment results