The fate of a polygenic phenotype within the genomic landscapes of introgression in the European seabass hybrid zone

Unraveling the evolutionary mechanisms and consequences of hybridization is a major concern in biology. Many studies have documented the interplay between recombination and selection in modulating the genomic landscape of introgression, but few have considered how associations with phenotype may affect this landscape. Here, we use the European seabass (Dicentrarchus labrax), a key species in marine aquaculture that undergoes natural hybridization, to determine how selection on phenotype modulates the introgression landscape between Atlantic and Mediterranean lineages. We use a high-density SNP array to assess individual local ancestry along the genome and improve the mapping of muscle fat content, a polygenic trait that is divergent between lineages. Taking into account variation in recombination rates, we reveal a purging of Atlantic ancestry in the admixed Mediterranean populations. While Atlantic individuals had higher muscle fat content, we observed that genomic regions associated with this trait also displayed reduced introgression of Atlantic ancestry. These results emphasize how selection against maladapted alleles shape the genomic landscape of introgression.

Unraveling the evolutionary mechanisms and consequences of hybridization is a major concern in biology. Many studies have documented the interplay between recombination and selection in modulating the genomic landscape of introgression, but few have considered how associations with phenotype may affect this landscape. Here, we use the European seabass (Dicentrarchus labrax), a key species in marine aquaculture that undergoes natural hybridization, to determine how selection on phenotype modulates the introgression landscape between Atlantic and Mediterranean lineages. We use a high-density SNP array to assess individual local ancestry along the genome and improve the mapping of muscle fat content, a polygenic trait that is divergent between lineages. Taking into account variation in recombination rates, we reveal a purging of Atlantic ancestry in the admixed Mediterranean populations. While Atlantic individuals had higher muscle fat content, we observed that genomic regions associated with this trait also displayed reduced introgression of Atlantic ancestry. These results emphasize how selection against maladapted alleles shape the genomic landscape of introgression.

Disciplines

Environment

Keywords

Hybridization, Introgression, phenotype, European seabass, selection, recombination

Location

52.682543N, 29.208993S, 36.71703E, -22.34547W

Devices

Genotyping data obtained by DLabCHIP Axiom SNP array (Griot et al, 2020, https://doi.org/10.1016/j.aquaculture.2020.735930)

Data

FileSizeFormatProcessingAccessend of embargo
Genotyping data in VCF format for Offspring and parents
353 MoVCFRaw data 2024-07-01
How to cite
Leitwein Maeva, Durif Ghislain, Delpuech Emilie, Gagnaire Pierre-Alexandre, Ernande Bruno, Vandeputte Marc, Vergnet Alain, Duranton Maud, Clota Frederic, Allal Francois (2020). The fate of a polygenic phenotype within the genomic landscapes of introgression in the European seabass hybrid zone. SEANOE. https://doi.org/10.17882/98771

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