Phylogeographic inferences on the native brown trout mtDNA variation in central Italy

Abstract

Genetic diversity was analysed in Salmo trutta populations living in an area of central Italy by sequencing 310 bp of the 59 end of the mtDNA control region (D-loop) and by Restriction Fragment Length Polymorphism (RFLP) analysis of three mtDNA segments. Data show a genetic structure profoundly altered by stockings with allochthonous material of Atlantic origin. In fact, 15 of the RFLP haplotypes detected are linked to an Atlantic sequence. The remaining 9 were instead coupled with sequences representing the three major phylogenetic lineages previously identified in the Mediterranean basin (Adriatic, marmoratus, and Mediterranean), representing the native genetic diversity of brown trout in that area. The close genetic affinity observed between these latter haplotypes and those found in the Balkan peninsula by other authors seems to be in accordance with a recent, natural, history of dispersion between the two borders of the Adriatic Sea. These results appear significant from a conservation point of view as, in spite of the massive stocking with hatchery-reared specimens, they highlight the persistence of Salmo trutta native genetic diversity in central Italy.

Genetic characterization of brown trout (Salmo trutta) populations from the Southern Balkans using mtDNA sequencing and RFLP analysis

“…The coexistence of highly differentiated haplotypes in a relatively small geographic area highlights that in the Southern Balkans, as in other areas of the Mediterranean basin (e.g. Splendiani et al, 2006), mitochondrial haplotypes are distributed in a mosaic pattern as a consequence of a complex evolutionary history. The topology of both the NJ and MP trees agrees with the proposed evolutionary model of the brown trout complex, where the most ancient phylogeographical separation involved allopatric fragmentation between the three major European drainages: the Atlantic (AT lineage), the Ponto-Caspian (DA lineage) and the Mediterranean basin (the common branch for the AD, MA, and ME lineages).…”

Chromosomal study of native and hatchery trouts from Italy (<i>Salmo trutta </i>complex, Salmonidae): conventional and FISH analysis

“…From each individual a sample of blood was taken for establishing lymphocyte cultures (Fujiwara et al, 2001), and a fin clip was collected for DNA extraction (Sambrook et al, 1989). The specimens used for the cytogenetic study were assigned to the lineages occurring in Italy by PCR-RFLP analysis of three mtDNA segments (ND-1, ND-3/4, ND-5/6) and the LDH-C1 * locus, with the * 90 allele fixed in north-western Europe, and the * 100 allele common in the Mediterranean basin (McMeel et al, 2001;Splendiani et al, 2006). Oncorhynchus mykiss Walbaum metaphases and genomic DNA of Salmo salar Linnaeus and O. mykiss obtained from commercially available specimens were used for cytogenetic and molecular comparisons.…”

“…Besides these autochthonous lineages, the Atlantic lineage sensu Bernatchez (2001) (At) is now also widely represented in Italian wild populations of the S . trutta complex (e.g., Caputo et al, 2004;Splendiani et al, 2006), owing to the massive stockings with farmed specimens of central and northern European origin (Bianco, 1995). From a systematic point of view, various taxa previously synonymized with Salmo trutta were recently recognized as separate species in Italy: Salmo carpio Linnaeus and S. marmoratus Cuvier in the northern regions; S. cenerinus Chiereghini in the northern regions and on the Adriatic side; S. cetti Rafinesque and S. fibreni Zerunian and Gandolfi for the Tyrrhenian drainages (Kottelat and Freyhof, 2007).…”

Re‐evaluation ofSalmodata by Gridelli (1936)—description of stocking, hybridization and repopulation in the River Soča basin

“…Native trout species of the rivers flowing into the Mediterranean have been severely affected by the introduction of non-native Salmo trutta (brown trout) during the twentieth century, both in the drainage area of Thyrrenian and Western Adriatic Seas in central Italy (Lucentini et al 2006;Splendiani et al 2006) and in the drainage area of the Northern and Eastern Adriatic Sea (Vuković 1982;Povž & Sket 1990). Hybridization of native and introduced trouts is widespread and only recently adopted legislation in some countries prohibits the stocking of rivers with non-native trout.…”