Mediterranean trout (Salmo cettii) is a freshwater fish with economic significance for fisheries management, aquaculture, and conservation biology. Unfortunately, native trout populations’ abundance is significantly threatened by anthropogenic disturbance and the introduction of commercial hatchery strains of Salmo trutta for recreation activities has compromised the genetic integrity of native trout. This work assesses the genetic structure of Mediterranean trout of the main streams of Molise region (Biferno and Volturno rivers), considering that no previous genetic population structure data are available. Ultimately, this research aims to provide useful information to be considered in conservation management. In total, 288 specimens were caught in 30 different sites (15 per basins). Adipose fin tissues were collected and DNA isolated. Samples were genotyped using the Affymetrix 57K SNP-array. Sample and SNP quality control were applied considering no-call threshold of 0.05 and missing data cut-off of 0.90. SNP with a minor allele frequency below 0.05 were discarded. Since no animals were discarded the final dataset consisted of 288 specimens and 920 polymorphic SNP. Population differentiation was analyzed using global weighted average F-statistic over loci and pairwise FST among sampling sites. All tests were implemented in Arlequin software. The SNP data set was also processed through principal component analysis and Bayesian clustering analysis using Plink and ADMIXTURE software, respectively. Our data provided a good representation of the population structure of Molise Mediterranean trout at finescale and results indicate a high degree of introgression and genetic admixture among introduced Atlantic lineage and native trout, particularly on Biferno river, where the population seems to be exposed to a high risk of genetic integrity loss. In Volturno basin, a high proportion of genetically low-introgressed trout was found strictly connected with the role of artificial and natural barriers. Subpopulations within each river and their related habitats were identified. These outcomes provide useful information to preserve native species in conservation and management programs. In conclusion, this work provided an insight into the genetic relationships and spatial distribution of populations in Molise rivers and the first use of SNP-array technology in research of Italian trout population.
Genetic biodiversity study in Mediterranean trout population using SNP array: a case study in Molise region
PALOMBO V.;SALVATORE G.;ALBANESE G.;IORIZZO M.;RUSCO G.;DI IORIO M.;IAFFALDANO N.;
2021-01-01
Abstract
Mediterranean trout (Salmo cettii) is a freshwater fish with economic significance for fisheries management, aquaculture, and conservation biology. Unfortunately, native trout populations’ abundance is significantly threatened by anthropogenic disturbance and the introduction of commercial hatchery strains of Salmo trutta for recreation activities has compromised the genetic integrity of native trout. This work assesses the genetic structure of Mediterranean trout of the main streams of Molise region (Biferno and Volturno rivers), considering that no previous genetic population structure data are available. Ultimately, this research aims to provide useful information to be considered in conservation management. In total, 288 specimens were caught in 30 different sites (15 per basins). Adipose fin tissues were collected and DNA isolated. Samples were genotyped using the Affymetrix 57K SNP-array. Sample and SNP quality control were applied considering no-call threshold of 0.05 and missing data cut-off of 0.90. SNP with a minor allele frequency below 0.05 were discarded. Since no animals were discarded the final dataset consisted of 288 specimens and 920 polymorphic SNP. Population differentiation was analyzed using global weighted average F-statistic over loci and pairwise FST among sampling sites. All tests were implemented in Arlequin software. The SNP data set was also processed through principal component analysis and Bayesian clustering analysis using Plink and ADMIXTURE software, respectively. Our data provided a good representation of the population structure of Molise Mediterranean trout at finescale and results indicate a high degree of introgression and genetic admixture among introduced Atlantic lineage and native trout, particularly on Biferno river, where the population seems to be exposed to a high risk of genetic integrity loss. In Volturno basin, a high proportion of genetically low-introgressed trout was found strictly connected with the role of artificial and natural barriers. Subpopulations within each river and their related habitats were identified. These outcomes provide useful information to preserve native species in conservation and management programs. In conclusion, this work provided an insight into the genetic relationships and spatial distribution of populations in Molise rivers and the first use of SNP-array technology in research of Italian trout population.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
