Segregation of microsatellite loci in second generation hybrid striped bass (Morone saxatilis × Morone chrysops)

Abstract

Within the framework of a larger project aimed to assess the potential of second generation hybrid striped bass for German aquaculture the genotypic segregation of five microsatellite loci was analysed in two progeny lots (n = 74 and 76, respectively). There was no consistent correlation between microsatellite genotypes and phenotypic category (white bass, hybrid, or striped bass). None of the individuals expressed neither only white bass nor only striped bass genotypes at all five loci. On the other hand, only hybrid genotypes at all five loci were detected in three individuals of lot 1 and four individuals of lot 2. Single loci tests for conformity of microsatellite genotypic segregation with Mendelian rules revealed significant deviations (P \ 0.05) in four cases for lot 1 and in three cases for lot 2. If pooled over all five loci, both lots displayed highly significant deviations (P \ 0.01) with an excess of hybrid genotypes and a deficiency of white bass genotypes. It is concluded that stabilizing selection performed on hybrid genotypes might be a suitable approach for practical aquaculture in Europe if the goal is to become independent of first generation hybrid fry supply and/or if establishing domesticated brood stocks of both parental species is impossible. However, more detailed studies on the characteristics and performance of multiple hybrid generations are needed.

First record of a hybrid striped bass (Morone saxatilis × Morone chrysops ) in the Danube River

“…Nine of the 12 possible alleles had already been found in F1 and/or F2 HSB by Kohlmann et al. (). The remaining three alleles were within the size ranges reported for white or striped bass by Ross et al.…”

“…It was stored frozen at −20°C until May 2011, when it was measured and photographed. Standard length (SL) and total length (TL) were measured to the nearest 1 mm, while the body mass was measured to the nearest 0.1 g. A sample of the caudal fin was stored in 99.9% ethanol, and later sent to the Leibniz‐Institute of Freshwater Ecology and Inland Fisheries (Berlin, Germany) for genotyping of six microsatellites suitable for distinguishing between striped bass, white bass and their hybrid (Kohlmann et al., ). DNA isolation, PCR amplification of microsatellites, and their genotyping on an automated capillary sequencer CEQ 8000 (Beckman Coulter) were performed as described in Kohlmann et al.…”

“…DNA isolation, PCR amplification of microsatellites, and their genotyping on an automated capillary sequencer CEQ 8000 (Beckman Coulter) were performed as described in Kohlmann et al. (). Otoliths were removed for age determination, while the sex was determined by macroscopic examination of gonads.…”

“…The first introduction of the striped bass ( Morone saxatilis ) in Europe was in the former USSR for aquaculture purposes in 1965 (Holčík, ). Production of hybrid striped bass (HSB) for aquaculture, by crossing striped bass with the white bass ( Morone chrysops ), is of growing interest in Europe (Kohlmann et al., ). Since the 1980s, HSB were increasingly imported into Mediterranean and European countries, first to Israel and later to Germany, Italy, Turkey and Hungary (Innal and Erk'akan, ; Kottelat and Freyhof, ; Roll et al., ).…”

“…According to Kohlmann et al. (), Italy and Israel are two of the major HSB producers in the world. Neither stocked nor escaped HSB specimens have yet established populations in European open waters (Innal and Erk'akan, ; Kottelat and Freyhof, ; Roll et al., ).…”