Using horizontal agarose thin layer gel electrophoresis, 35 allozyme loci were screened in 233 brown trout (Salmo trutta L.) from 11 populations in southwest Germany across the RhenanianDanubian watershed. Polymorphism was found at 10 loci, with stocked populations exhibiting significantly increased polymorphism compared with unmanaged stocks (P= 0.2 19 vs. P= 0.132). Standard genetic distances between populations from different brooks averaged at D =0.01. Of the total gene diversity of GST =0.198, only a negligible amount partitioned between Rhenanian and Danubian drainages (GGT= 0.0 10). One biallelic locus, LDH5*, indicated river-specific allele frequencies, with the allele LDH-5 *105 being markedly more frequent within the Danubian drainage system. In contrast, LDH-5 *100 was close to fixation in the Rhenanian populations. This locus suggests a phylogeographical relationship of Danubian trout from southwest Germany with brown trout from southeastern Europe rather than with conspecifics of adjacent Rhenanian origin.

The morphological differentiation between four population collectives of the Central European sculpin Cottus gobio from southwestern Germany and adjacent France (the contact region of the Rhine, Danube, and Rhône drainage basins) was evaluated using multivariate analysis of 34 morphometric and 3 meristic characters. Body shape separated Neckarian and Danubian sculpins, Rhenish stocks taking a somewhat intermediate position. These morphological differences between populations from various drainage basins were slighter than the deeper allozyme differentiation observed in a previous study. However, both allozymes and morphometry indicated the same population groupings. It is concluded that C. gobio displays an accelerated rate of allozyme evolution, or that stabilizing selection conserves its phenotype despite ongoing evolution at the protein level. The morphological data do not support the distinction of species in the area of the Rhine/Danube watershed.

Population genetic affinities of 261 European sculpins Cottus gobio L. across the Rhenanian‐Danubian and the Rhenanian‐Rhónian watersheds were assessed by horizontal agarose‐gel electrophoresis of up to 20 allozyme systems (encoded by 29 genetic loci). Polymorphism Pmean= 0.0689 (range: 0.000‐0.1379), and heterozygosity He(mean)= 0.0167 (range: 0.000‐0.0507) indicated low genetic variability within local stocks from single streams. Significant genetic distances Dmean= 0.1917 ± 0.0336 (Dmax= 0.2407), based on differential fixation at 3–6 loci (Acp‐1**, Pgdh**, Fh**, Est‐1**, Gpi‐2**, and Pgm‐1**) distinguished populations from the Neckar catchment basin from those of the Hochhrein‐Oberrhein and Danube basins. Differential fixation of alleles and pronounced genetic distances also separated sculpins of the Rh6nian tributary Doubs from Neckarian populations (Dmen= 0.2131 ± 0.0033; Ah**, Acp‐1**, Fh**), of the Doubs from the Danube (Dmean= 0.2177 ± 0.0028; Gpi‐2**, Pgm‐1**, Pgdh**, Ah**), and of the Doubs from the Hochrhein‐Oberrhein (Dmean= 0.1780; Pgm‐1**, Pgdh**, Ah**). Genetic distances between streams within these drainages proved low (Neckar: Dmen= 0.0047 ± 0.0014, Danube: Dmean= 0.026 ± 0.0179, Rhine: Dmean= 0.0308). Screening of another 16 small‐size samples consisting of 55 sculpins for nine diagnostic loci (Aat‐2**, Acp‐1**, Acp‐2**, Ah**, Est‐1**, Fh**, Gpi‐2**, Pgdh** and Pgm‐1**) confirmed the genetic homogeneity of sculpins within the Danubian and Neckarian drainage systems, but Neckarian sculpins were similar to those from the river Main. Populations from Hochrhein‐Oberrhein resembled the Danubian stock but contained a decreasing frequency of ‘Neckarian’ markers when approaching the Danubian region. The genetic divergence between Neckarian, Danubian and Rhdnian sculpins suggests the existence of hitherto neglected taxa of anteglacial divergence.

No abstract

Population genetic affinities of 261 European sculpins Cottus gobio L. across the Rhenanian‐Danubian and the Rhenanian‐Rhônian watersheds were assessed by horizontal agarose‐gel electrophoresis of up to 20 allozyme systems (encoded by 29 genetic loci). Polymorphism Pmean = 0.0689 (range: 0.000–0.1379), and heterozygosity He(mean) = 0.0167 (range: 0.000–0.0507) indicated low genetic variability within local stocks from single streams. Significant genetic distances Dmean = 0.1917 ± 0.0336 (Dmax = 0.2407), based on differential fixation at 3–6 loci (Acp‐I**, Pgdh**, Fh**, Est‐1**, Gpi‐2**, and Pgm‐1**) distinguished populations from the Neckar catchment basin from those of the Hochhrein‐Oberrhein and Danube basins. Differential fixation of alleles and pronounced genetic distances also separated sculpins of the Rhônian tributary Doubs from Neckarian populations (Dmean = 0.2131 ± 0.0033; Ah**, Acp‐1**, Fh**), of the Doubs from the Danube (Dmean = 0.2177 ± + 0.0028; Gpi‐2**, Pgm‐1**, Pgdh**, Ah**), and of the Doubs from the Hochrhein‐Oberrhein (Dmean = 0.1780; Pgm‐1**, Pgdh**, Ah**). Genetic distances between streams within these drainages proved low (Neckar: Dmean = 0.0047 ± 0.0014, Danube: Dmean = 0.026 ± 0.0179, Rhine: Dmean = 0.0308). Screening of another 16 small‐size samples consisting of 55 sculpins for nine diagnostic loci (Aat‐2**, Acp‐1**, Acp‐2**, Ah**, Est‐1**, Fh**, Gpi‐2**, Pgdh** and Pgm‐1**) confirmed the genetic homogeneity of sculpins within the Danubian and Neckarian drainage systems, but Neckarian sculpins were similar to those from the river Main. Populations from Hochrhein‐Oberrhein resembled the Danubian stock but contained a decreasing frequency of ‘Neckarian’ markers when approaching the Danubian region. The genetic divergence between Neckarian, Danubian and Rhônian sculpins suggests the existence of hitherto neglected taxa of anteglacial divergence. Zusammenfassung Disjunkte genetische Populationsstruktur bei mitteleuropäischen Mühlkoppen (Cottus gobio L.): Folge verschiedener Einwanderungswellen oder genetischer Drift? Mit Hilfe von Agarose‐Dünnschicht‐Gelelektrophorese von 20 Allozymsystemen, die von 29 genetischen Loci kodiert werden, wurde die genetische Differenzierung von neun Mühlkoppenpopulationen Cottus gobio L. mit insgesamt 206 Individuen aus den Gewässersystemen von Donau, Rhein und Rhône ermittelt. Der durchschnittliche Polymorphisms betrug Pmean = 0.0689 (0.000–0.1379), der erwartete Heterozygotiegrad He = 0.0167 (0.000–0.0507). Bis zu sechs (Acp‐1**, Pgdh**, Fh**, Est‐1**, Gpi‐2** und Pgm‐1**) für unterschiedliche Allele fixierte Loci zwischen den Populationen des Neckareinzugsgebietes und jenen der Donau, des Ober‐ und Hochrheins resultierten in einer durchschnittlichen genetischen Distanz von Dmean = 0.1917 ± 0.0336 (Dmax = 0.2407). Beträchtliche genetische Distanzen aufgrund entgegengesetzter Homozygotie wurden auch zwischen den Mühlkoppen des Doubs und jenen der anderen Gewässersysteme aufgedeckt: Doubs‐Neckar (Dmean = 0.2131 ± 0.0033; Ah**, Acp‐1**, Fh**), Doubs‐Do...