Costas Tsigenopoulos

Publications (65) View all

• Source

  Available from: Bruno Guinand

  Article: Gene flow at major transitional areas in sea bass (Dicentrarchus labrax) and the possible emergence of a hybrid swarm

  Nolwenn Qué Ré, Erick Desmarais, Costas S Tsigenopoulos, Khalid Belkhir, François Bonhomme, Bruno Guinand
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  ABSTRACT: The population genetic structure of sea bass (Dicentrarchus labrax) along a transect from the Atlantic Ocean (AO) to the Eastern Mediterranean (EM) Sea differs from that of most other marine taxa in this area. Three populations (AO, Western Mediterranean [WM], EM) are recognized today, which were originally two allopatric populations. How two ancestral genetic units have evolved into three distinct units has not been addressed yet. Therefore, to inves-tigate mechanisms that lead to the emergence of the central WM population, its current status, and its connectivity with the two parental populations, we applied 20 nuclear loci that were either gene associated or gene independent. Results confirmed the existence of three distinct gene pools, with higher differ-entiation at two transitional areas, the Almeria-Oran Front (AOF) and of the Siculo-Tunisian Strait (STS), than within any population. Significant linkage disequilibrium and heterozygote excess indicated that the STS is probably another tension zone, as already described for the AOF. Neutrality tests fail to reveal marker loci that could be driven by selection within or among metapop-ulations, except for locus DLA0068. Collectively, results support that the central WM population arose by trapping two tensions zones at distinct geographic locations of limited connectivity. Population assignment further revealed that WM individuals were more introgressed than individuals from the other two metapopulations. This suggests that this population might result from hybrid swarming, and was or is still seeded by genes received through the filter of each tension zone.
  Ecology and Evolution. 12/2012; 2(12):3061-3078.
• Source

  Available from: Costas Tsigenopoulos

  Article: Gene flow at major transitional areas in sea bass (Dicentrarchus labrax) and the possible emergence of a hybrid swarm.

  Nolwenn Quéré, Erick Desmarais, Costas S Tsigenopoulos, Khalid Belkhir, François Bonhomme, Bruno Guinand
  [show abstract] [hide abstract]
  ABSTRACT: The population genetic structure of sea bass (Dicentrarchus labrax) along a transect from the Atlantic Ocean (AO) to the Eastern Mediterranean (EM) Sea differs from that of most other marine taxa in this area. Three populations (AO, Western Mediterranean [WM], EM) are recognized today, which were originally two allopatric populations. How two ancestral genetic units have evolved into three distinct units has not been addressed yet. Therefore, to investigate mechanisms that lead to the emergence of the central WM population, its current status, and its connectivity with the two parental populations, we applied 20 nuclear loci that were either gene associated or gene independent. Results confirmed the existence of three distinct gene pools, with higher differentiation at two transitional areas, the Almeria-Oran Front (AOF) and of the Siculo-Tunisian Strait (STS), than within any population. Significant linkage disequilibrium and heterozygote excess indicated that the STS is probably another tension zone, as already described for the AOF. Neutrality tests fail to reveal marker loci that could be driven by selection within or among metapopulations, except for locus DLA0068. Collectively, results support that the central WM population arose by trapping two tensions zones at distinct geographic locations of limited connectivity. Population assignment further revealed that WM individuals were more introgressed than individuals from the other two metapopulations. This suggests that this population might result from hybrid swarming, and was or is still seeded by genes received through the filter of each tension zone.
  Ecology and evolution. 12/2012; 2(12):3061-78.
• Source

  Available from: Costas Tsigenopoulos

  Article: Description of microsatellite markers in four mullids based on the development and cross-species amplification of 18 new markers in red mullet (Mullus barbatus)

  Emmanouella Vogiatzi, Reinhold Hanel, Thanos Dailianis, Jacques Lagnel, Mohamad Hassan, Antonios Magoulas, Costas S. Tsigenopoulos
  Biochemical Systematics and Ecology 10/2012; 44:279-285. · 0.93 Impact Factor
• Source

  Available from: Costas Tsigenopoulos

  Article: Characterization of polymorphic microsatellite markers in Valencia letourneuxi (Valenciidae) and cross-amplification in two other cyprinodontiform species

  Emmanouella Vogiatzi, Eleni Kalogianni, Sofia Giakoumi, Antonios Magoulas, Costas S. Tsigenopoulos
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  ABSTRACT: Fourteen microsatellite loci were isolated from the critically endangered Corfu toothcarp Valencia letourneuxi using a microsatellite enrichment protocol and selective hybridization with a biotinylated (AC) probe. Nine of these loci were polymorphic in a V. letourneuxi population of 20 individuals (Vlychos stream) with mean number of alleles per locus=2.55 and mean observed heterozygosity=0.3447. Moreover, some of these 9 microsatellite markers and the remaining five loci, monomorphic in V. letourneuxi, were found to be polymorphic in the Spanish samaruc Valencia hispanica and the Mediterranean toothcarp Aphanius fasciatus. These microsatellite loci are expected to be used for population genetic analysis as well as studying the genetic diversity of this endangered species.
  Conservation Genetics Resources 05/2012; 1(1):27-30. · 0.49 Impact Factor
• Article: QTL affecting morphometric traits and stress response in the gilthead seabream (Sparus aurata)

  Kay Boulton, Cecile Massault, Ross D. Houston, Dirk Jan de Koning, Chris S. Haley, Henk Bovenhuis, Costas Batargias, Adelino V.M. Canario, Giorgios Kotoulas, Costas S. Tsigenopoulos
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  ABSTRACT: The gilthead seabream (Sparus aurata) is an important aquaculture species that has only been subject to an incipient selective breeding programme. This study, which examined the genetic architecture of seabream morphology and stress response to confinement, takes a step toward the use of marker assisted selection in this species. Major loci affecting these traits were mapped, using data from 460 offspring derived from seven paternal and 73 maternal half-sib families. Fish were killed following a four-hour confinement experiment to induce stress, after which 15 morphometric measurements were collected and blood was sampled for DNA extraction and plasma cortisol level determination. Heritabilities for the morphometric traits were moderate to high (0.24–0.58), with genetic and phenotypic correlations between the traits generally very high. However, the heritability of plasma cortisol level was not significantly different from zero.A population-specific genetic linkage map was built for 56 microsatellite markers, comprising 16 linkage groups (LG) and ten unlinked markers. Half-sib and variance components QTL analyses detected a single genome-wide significant QTL (SaimbcF7b), a single unlinked marker explaining 13–23% of the phenotypic variance in the majority of the morphometric traits. Several other putative QTL were identified for morphometric traits (on LG 4a, 7, 9, 18, A, C, F and I), along with two other QTL (LG10 and B) that were suggestive for stress response. Fitting body weight as a covariate for the morphometric traits resulted in three genome-wide significant QTL affecting aspects of body shape independent of overall body size. For stress response we only identified suggestive evidence for QTL. These findings contribute to understanding the genetic regulation of important economic traits in seabream.
  Aquaculture 09/2011; 319:58-66. · 2.04 Impact Factor