Data from: Genetic monitoring of brown trout released into a novel environment: Establishment and genetic impact on natural populations
Data files
Feb 11, 2025 version files 816.05 KB
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Browntrout_individualDATA_96SNPs_.xlsx
786.88 KB
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Browntrout_TemporalAlleleFrequencies_G3PDH-2.xlsx
14.38 KB
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README.md
5.45 KB
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Waterway_distance.xlsx
9.36 KB
Abstract
Translocations are carried out either unintentionally or intentionally for conservation or management reasons. In both cases, translocated populations may genetically impact natural populations via introgression. Understanding how genetic background may affect establishment in a novel environment and the potential risks for native populations is important for biodiversity conservation. To address these issues, we studied a case of an intentional human-mediated release of two genetically and morphologically distinct brown trout populations released into a lake system previously void of this species. This dataset was used to monitor the establishment of, and hybridization between these two populations, as well as their genetic effect on naturally occurring brown trout below an upstream migration barrier. Morphological and ecological data (body size, sexual maturity) were used to examine wether differences observed between the released populations in their native environment still remained three decades after the release. Finally, the SNP panel was compared to previously used allozyme data to investigate if these marker systems provide similar pictures of population structure.
https://doi.org/10.5061/dryad.37pvmcvvq
Description of the data and file structure
This dataset contains raw data required to replicate the analyses in Andersson et al. (in review), examining population structure, genetic diversity, and divergence of introduced and natural brown trout populations in the Swedish subarctic. The water system studied is divided by a waterfall which prevents upstream migration. The area above the waterfall was void of brown trout before the release of the two populations in 1979, while the area below is inhabited by natural populations of stream-resident brown trout. Data from above the waterfall was used to address questions regarding establishment, hybridization, and phenotypic differences, while the data from the creek below the waterfall was utilized for assessing the rate of introgression from the introduced populations into the native ones over time and applying indicators for genetic monitoring. In addition, SNP data was compared with previously used allozymes to examine whether these two marker systems provide a similar picture of population structure. Results indicated that extensive hybridization between the introduced populations has taken place and both populations have spread their genes throughout the whole lake system. Morphological differences between the populations in their natural environment have to a large extent disappeared but some divergence with respect to migration behavior has remained. Introgression from above the waterfall into native creek populations has occurred, although it appears to be limited. The SNPs and allozymes provided a similar picture, showing that older marker systems with fewer loci may be useful for adequate description of population structure
This dataset includes individual genotypes (96 SNPs and one allozyme locus) and phenotypic data for the introduced brown trout populations and their descendants above the waterfall at two points in time (fish representing the released populations and contemporary samples from 2007-2015). It also includes genotypes (96 SNPs) for the natural populations below the waterfall from two localities at three points in time (before the release, 1999, and 2011). Allele frequencies at one allozyme locus (G3PDH-2; which was diagnostic in the two introduced populations due to contrasting homozygosity) spanning over three decades are also available for three lakes above the waterfall and the two creek localities.
Files and variables
File: Browntrout_individualDATA_96SNPs_.xlsx
Description: Individual genotypic, morphological, and ecological data for introduced and natural brown trout. The data for the introduced populations above the waterfall and the natural populations below the waterfall are stored in different sheets ("Above waterfall_DATA" and "Below waterfall_DATA", respectively). Single nucleotide polymorphism (SNP) genotypes are provided in a 2-column format with numerical values corresponding to the four bases (1=A, 2=C, 3=G, 4=T). Locus names and NCIDs corresponding to the locus designations used in the DATA sheets are provided in the sheet "Locus ID". All missing values are coded as "NA".
Variables
- Population: Represents a spatiotemporal sample. Genetic baselines for the two released populations, and the two creek populations before the release, Lake 1-7, Creek I-II (at two points in time).
- Individual_nbr: Serial number of the individual from a spatiotemporal sample.
- Catch_date: The date the individual was caught. The format is YYYY-MM-DD.
- Length_mm: Body length in millimeters.
- Age_yrs: Age in years. Based on otolith readings.
- Birth_year: Year of birth. Calculated as catch year – age.
- Sex: Male/Female.
- Maturity_status: Mature/Not mature. Mature=the fish would have spawned in the year it was caught. Based on assessment of gonadal development.
- G3PDH-2_genotype: Genotype at the G3PDH-2 allozyme locus. Genotypes are coded as 100/100=homozygous for the 100 allele, 100/50=heterozygous, 50/50=homozygous for the 50 allele.
- Locus1_1: First allele of the individual genotype at SNP locus 1 (for SNP locus IDs and NCIDs please see the sheet "Locus ID").
- Locus1_2 Second allele of the individual genotype at SNP locus 1.
- The following 190 columns (L-GS) contain genotypes at SNP Locus 2-96 in the same format as described for Locus 1 above.
File: Browntrout_TemporalAlleleFrequencies_G3PDH-2.xlsx
Description: Allele frequencies at the allozyme locus G3PDH-2 for three lakes above the waterfall and the two creek localities below the waterfall.
Variables
- Locality: Sampling locality.
- Sampling_year: Sampling year.
- Sample_size: The number of fish that constitute the basis for the allele frequency estimates.
- Frequency*allele*100: The frequency of the 100 allele.
- Frequency*allele*50: The frequency of the 50 allele.
File: Waterway_distance.xlsx
Description: Approximate waterway distances (in kilometers) of the seven lakes harboring descendants of the released populations from the release site.
Variables
- Lake: Lake designation.
- Approx_dist_from_release_locality_km: Approximate waterway distance in kilometers from the release site to each of the seven lakes.