Hybridization and restricted gene flow between native and introduced stocks of Alpine whitefish (Coregonus sp.) across multiple environments.
Bottom Line: Fifteen populations (N=747) were assessed for allelic variation at eight microsatellite loci and a reduced set (N=253) for variation across two mtDNA genes (cyt b and NADH-3).Although statistically congruent with inferences based on nuclear markers, mitochondrial haplotype data was not diagnostic with respect to native and non-native lineages, supporting that the Alpine region was colonized post-glacially by an admixture of mtDNA lineages, which coalesce >1 Ma.Mechanisms promoting or eroding lineage isolation are discussed, as well as a high potential to conserve native Alpine lineages despite the extensive historical use of introduced Baltic stocks.
Affiliation: Institute for Zoology, Karl-Franzens University Graz, Universitätsplatz 2, Graz, Austria.Show MeSH
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Mentions: Within population structure and levels of hybridization differed among lakes (Fig. 3). The WAL reference revealed a mean q-value of 0.09, with 79 out of 102 individuals fulfilling the criteria of ‘pure’ OU-introduced. Simulated admixture analyses were run with both the entire WAL sample, as well as the 79 ‘pure’ individuals, though little difference was revealed (Fig. 3). Six of 12 Austrian lakes (FUS, HAL, MON, NIE, OBE and WOL) harbour both OUs albeit in varying proportions. The OU-native was most abundant ranging from 36.1 (OBE) to 100% (KLO). Pure OU-introduced individuals were found to a lesser extent, with the highest proportions found in OBE (22.2%) and MON (20.2%). Hybrid proportions varied from 10.3 (WOL) up to 74.3% (ZEL). Most lakes revealed an s-formed distribution of assignment (q-values), although with an abrupt slope clearly distinguishing the two OUs and their hybrids compared to the simulated hybrid populations (including parents). Three lakes (MIL, WOE and ZEL) exhibited a more linear pattern indicating extensive introgression with a deficiency of pure OU-introduced individuals, suggesting the result of historical rather than contemporary processes. Three lakes ACH, KLO and KOP revealed no signal of hybridization reflecting the fact that no stocking with the OU-introduced has occurred (Table 1). Mean q-values in these lakes ranged from 0.94 (KOP) to 0.97 (KLO).
Affiliation: Institute for Zoology, Karl-Franzens University Graz, Universitätsplatz 2, Graz, Austria.