Asymmetrical hybridization and environmental factors influence the spatial genetic structure of a killifish hybrid zone

Hybridization offers insight into speciation and the forces that maintain barriers to reproduction, and hybrid zones provide excellent opportunities to test how environment shapes barriers to reproduction and hybrid fitness. A hybrid zone between the killifish, Fundulus heteroclitus and F. grandis, had been identified in northeastern Florida, although the spatial structure and parameters that affect the distribution of the two species remain unknown. The present study aimed to determine the fine-scale spatial genetic patterns of the hybrid zone to test the hypothesis that species ranges are influenced by changes in dominant vegetation, and to determine how differences in reproductive barriers between the two species influence the observed patterns. The area of overlap between the two species spanned ~37 km and showed a mosaic pattern of hybridization, suggesting the spatial structure of the hybrid zone is largely influenced by the environment. Environmental association analysis, however..., DNA was extracted from fin tip tissue of 431 total individuals of Fundulus heteroclitus, Fundulus grandis, and Fundulus hybrids. Library was prepared according to Peterson et al. 2012 (https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0037135) for ddRADseq using restriction endonucleases SphI-HF and MluCI and a size selection window of 375-450 base pairs. Individuals were sequenced in three separate lanes at the University of Florida Interdisciplinary Center for Biotechnology Research on an Illumina NovaSeq 6000 (S4, 2x100). Raw sequence reads were imported into the STACKS pipeline (Rochette et al. 2019; https://onlinelibrary.wiley.com/doi/abs/10.1111/mec.15253), PCR duplicates were removed, and sequences were demultiplexed. The data present here include all resulting demultiplexed sequences used in the project. , , # Asymmetrical hybridization and environmental factors influence the spatial genetic structure of a killifish hybrid zone

[https://doi.org/10.5061/dryad.wh70rxwxv](https://doi.org/10.5061/dryad.wh70rxwxv)

## Description of the data and file structure

Twelve non-reference sites were chosen for the present study to include as many locations as possible between Crescent Beach and Titusville, Florida to increase the resolution of the current borders and spatial genetic structure of the hybrid zone. Sample sites are listed north-south as follows: Matanzas Inlet (MI), Summer Haven (SH), Marineland (ML), Marineland South (MS), Bing’s Landing (BL), Herschel King (HK), Beverly Beach (BB), Flagler North (FN), Flagler Beach (FB), Highbridge (HB), Tomoka Basin (TB) and the Indian River Lagoon (IR) (coordinates in Supplemental Table 1). With the exception of IR, at least 30 individuals from each site were collected using minnow traps and cast nets (samples sizes shown in Supplemental Table 1). Fi...