Data from: Translocation precipitates natural hybridisation and pervasive introgression between marine gastropods with divergent developmental modes
Data files
May 02, 2024 version files 89.78 MB
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Hybridisation_manuscript_analyses_dryad.R
23.30 KB
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Hybridisation_manuscript_figures_dryad.R
8.42 KB
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metadata_dryad.xlsx
25.26 KB
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README.md
2.42 KB
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Report_DBemb21-6115_2_SNP_mapping_2.csv
89.72 MB
Abstract
Assisted colonisation, the introduction of species beyond their historical range, is increasingly necessary for conserving species. However, empirical evidence of the long-term genetic outcomes of assisted colonisation is grossly lacking. A risk associated with moving species beyond their native range is the possibility of interspecific hybridisation with a closely related species, potentially resulting in outbreeding depression or the genetic swamping of a parental species. Here, we use a combination of genome-wide Single Nucleotide Polymorphism (SNP) markers and mitochondrial DNA sequencing to determine the long-term genetic consequences of introducing the intertidal periwinkle Bembicium vittatum (a direct developer) beyond its native range and into the native range of its congener Bembicium auratum (a species with planktotrophic larval dispersal). We found novel evidence of natural, multigenerational hybridisation between marine invertebrates with different modes of development. Intriguingly, introgression was highly asymmetrical initially, but became more evenly bidirectional as the population became more admixed. There was a significant decline in the frequency of alleles from the introduced B. vittatum over time, providing evidence of genetic swamping. The present study also provides potential evidence of outbreeding depression, in the form of cytonuclear incompatibilities, leading to the observed pattern of asymmetrical introgression. This study reveals the potential for unexpected mixing between species when reproductive barriers are not well understood, resulting in failure of pure B. vittatum to persist at the translocation site, a major concern associated with assisted colonisation. Without long-term genetic monitoring interspecific hybridisation between B. vittatum and B. auratum would have gone undetected, highlighting the importance of long-term monitoring to detect unintentional negative consequences of conservation translocations. Successful assisted colonisation requires an understanding of the potential for interspecific hybridisation between the threatened species and closely related native species, to reduce the risk of adverse outcomes.
https://doi.org/10.5061/dryad.g4f4qrfz4
Description of the data and file structure
“Report_DBemb21-6115_2_SNP_mapping_2.csv” contains raw SNP genotype data generated by Diversity Arrays Technology for each individual used in the study. Each allele is scored in binary fashion (“1”=Presence and “0”=Absence) and heterozygotes are scored as 1/1 (presence for both alleles/both rows).
Locus metatdata is also contained in this file (generated by DArT) including allele identification (AlleleID), the seaquence of each allele (AlleleSequence), average count of the reference (AvgCountRef) and SNP allele (AvgCountSnp), average polymorphism content of each locus (AvgPIC), locus call rate (CallRate), a unique identifier for the sequence that each SNP occurs in (CloneID), the proportion of samples scored as heterozygotes for each locus (FreqHets), the proportion of samples scored as homozygous for the reference allele (FreqHomRef) and SNP allele (FreqHomSnp), the polymorphism information content for the reference allele (PICRef) and the SNP allele (PICSnp), the proportion of technical replicates where the marker score is consistent (RepAvg), the position within the sequence tag where the SNP occurs (SnpPosition), and a trimmed version of the full sequence, but with adapters removed in shorter marker tags (TrimmedSequence).
“metadata_dryad.xlsx” contains individual metadata, including individual identification, population code, year collected, latitude, longitude, species classification and haplotype information based on 12S sequences for individuals collected in Fremantle and the B. vittatum and B. auratum source populations. Haplotype information was not obtained from B. auratum individuals from Albany or Rocky Bay as it was not relevant to the study and haplotype information is missing for some individuals collected from Fremantle due to an insufficient amount of DNA left by that stage in the project. In these cases, columns “Species haplotype”, “Haplotype” and “GenBank Accession” have been left blank.
“Hybridisation_manuscript_analyses_dryad.R” contains the code used to conduct all analyses for this study and “Hybridisation_manuscript_figures_dryad.R” contains the code used to create all figures.