- Email: [email protected]
Markers and methods for detecting introgression on hybridised populations
Abstracts / Aquaculture 272S1 (2007) S238–S321
modify with temperature the normal way of sex differentiation during embryogenesis in O. niloticus, before the onset of the gonadogenesis. XX males and females were used to produce XX progenies (n = 4). Shortly after fertilization (b 12 h), eggs were removed from the mouth of the female and were incubated at 27 ° C (control group), 34, 35 and 36 °C during the embryonic development. Experimental temperature was reached within 3 h, and was cool down at 30 °C within 24 h after hatching. At the age of 2 months (MBW = 3 g), sex ratios were determined with the acetocarmin squash method. Sex ratios of the control group were 100% females whereas a significant proportion of males (mean: 10.3, 17.9 and 20.0% at 34, 35 and 36 °C respectively) appeared in treated groups. These results prove that the normal way of sex differentiation could be modified before the onset of gonadogenesis, the temperature acting directly on the brain probably by inhibiting the expression of the gene coding for the brain aromatase. These results could confirm the role of the brain in the sex differentiation process and allow us to hypothesize for the first time on the “sexualisation” of the brain in tilapia. doi:10.1016/j.aquaculture.2007.07.176
QTL analysis for spawning date in ayu (Plecoglossus altivelis) on three-generation family T. Sakamoto a, H. Koshio a, M. Okochi a, Y. Watababe b, H. Hara b, H. Aikawa b, H. Fukuda a, N. Okamoto a a Department of Marine Biosciences, Faculty of Marine Science, Tokyo University of Marine Science and Technology, Tokyo, Japan b Kanagawa Prefecture Fisheries Research Institute, Kanagawa, Japan Construction of a genetic map based on DNA markers at a large number of sites in the fish genome is necessary to identify quantitative trait loci (QTL) controlling traits of economic importance to aquaculture (e.g. disease resistance, growth and spawning time). To search for QTL associated with spawning date in Ayu (Plecoglossus altivelis), we have constructed a genetic linkage map using 163 microsatellite markers. In the previous study, we have mapped fifteen QTL markers for spawning date representing six linkage groups in a backcross family produced by crossing two stains that differ in spawning date. Four of these QTL markers located on two linkage groups showed significant association with spawning date in another backcross
S307
families. In this study, we have performed QTL analysis on three-generation family to track the linkage between a trait and markers through next generations. We have mapped newly seven QTL markers for spawning date representing 4 linkage groups in the backcross family. Total nine QTL markers (two QTL markers in previous study) were analyzed on next generations. Two of these QTL markers located on two linkage groups have shown significant association with spawning date on second-generation family. One of these QTL markers has demonstrated significant association on third-generation family. These results suggest that this trait is polygenic, and these QTL markers could be possible to use for marker-assisted selection. doi:10.1016/j.aquaculture.2007.07.177
Markers and methods for detecting introgression on hybridised populations N. Sanz, R.M. Araguas, R. Fernandez, M. Vera, J.L. Garcia Marin Girona University, Biology, Campus Montilivi, 17071 Girona, Spain Many years of hybridization between native and cultivated individuals of Salmo trutta in the Iberian Peninsula, have led to different levels of hatchery introgression in natural populations. For many years, allozymes data and complete mtDNA control region sequences have been used to analyze the ongoing processes of human mediated hybridization. More recently, the appearance of higher polymorphic genetic markers (microsatellites) and new statistical approaches (Bayesian-based methods) have provided new tools to improve the evaluation of these introgression processes. We assess the effectiveness of three modelbased Bayesian methods (Structure, Newhybrids and Geneclass) in nine wild samples of S. trutta from the Iberian Peninsula using allozymes and microsatellites markers to detect hatchery introgression. Additional data from mtDNA have also been included in order to compare introgression estimates obtained by nuclear and mitochondrial markers. Results showed the importance of considering a large number of genetic markers and methods to evaluate introgression accurately. Implications of these results to decide what to conserve and which is the best policy to avoid the extinction of the remaining native populations are also
S308
Abstracts / Aquaculture 272S1 (2007) S238–S321
discussed. Keywords: Allozyme, Assignment test, Brown trout, Introgression, Microsatellite, mtDNA. doi:10.1016/j.aquaculture.2007.07.178
A gene-based radiation hybrid map of the gilthead sea bream Sparus aurata E. Sarropoulou a, G. Kotoulas a , L. Bargelloni b, D.M. Power c, R. Franch b, B. Louro c, A. Magoulas a, T. Patarnello f, F. Senger d, F. Galibert d, R. Geisler e a Institute of Marine Biology of Crete, Department of Genetics and Molecular Biotechnology, P.O. Box 2214, 710 03 Iraklio, Crete, Greece b Universita di Padova, Dipartimento di Sanita Pubblica, Patologia Comparata e Igiene Veterinaria, 35020 Legnaro, Italy c Center for Marine Science-CCMar, Universidade do Algarve, 8000-117 Faro, Portugal d UMR6061 CNRS, Genetique et Developpement, Faculte de Medecine, 35043 Rennes Cedex, France e Max-Planck-Institut fuer Entwicklungsbiologie, Abt. IIIGenetik, Spemannstrasse 35, 72076 Tuebingen, Germany f Department of Biology, University of Padova, via G. Colombo 3, 35131 Padova, Italy Comparative genomics is very promising for retrieving genomic information from fully sequenced model species to non-model species of high economic importance and/or species interesting from a biological or evolutionary aspect. One powerful method that allows comparative genome analysis has been shown to be comparative mapping. For teleosts of commercial interest genomic tools and resources facilitating comparative studies are under development. Among different mapping methods the radiation hybrid mapping results in dense and reliable genome maps for comparative use, since unlike linkage mapping, it permits to map coding regions as easily as neutral markers. In this study we present a first approach to comparative genomics by radiation hybrid mapping of the gilthead sea bream Sparus aurata, a non-model fish species of commercial and evolutionary interest, as representing the worldwide distributed species rich family of Sparidae, within the Perciformes. We were able to map 516 gene-based markers appropriate for comparative mapping studies. Data analysis has highlighted synteny conservation and similarity of gene order of sea bream to extensive studied model fish species like zebrafish, medaka, fugu and tetraodon and revealed evolutionary conserved regions and regions where
breakpoints occurred. Furthermore useful insights and tools for selective breeding came from the integration of the RH map with a linkage map, based on microsatellite markers that have been mapped on both. This genebased anchoring of radiation hybrid map on model species pinpoints to polymorphic microsatellite markers mapping near genes of interest as priority ones for QTL mapping and marker assisted selection. doi:10.1016/j.aquaculture.2007.07.179
Analysis and characterization of genes involved in immune functions isolated from the gilthead sea bream Sparus aurata and the European sea bass Dicentrarchus labrax infected with Vibrio anguillarum or nodavirus E. Sarropoulou a, P. Sepulcreb b, V. Mulero b, J. Meseguer b, L. Poisa c, S. Dios c, A. Figueras c, B. Novoa c, V. Terzoglou a, M. Kube d, R. Reinhardt d, G. Kotoulas a a Institute of Marine Biology of Crete, Department of Genetics and Molecular Biotechnology, P.O. Box 2214, 710 03 Iraklio, Crete, Greece b Department of Cell Biology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain c Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Científicas-CSIC. Eduardo Cabello, 6. 36208, Vigo, Spain d Max-Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin-Dahlem, Germany The gilthead sea bream (Sparus aurata) and the European sea bass (Dicentrachus labrax) are species of the main European aquaculture products and therefore prospective model species for the Perciformes, which includes several other commercially important species. Analysis of genes involved in immune functions contributes to gene expression studies, isolation of biomarkers as well as to the development of molecular resources for functional genomics. Although gene resources in marine fish species increase rapidly they lag behind those of other agricultural animals and only scanty information about the genetic source of phenotypic variation and the identity of quantitative trait loci (QTL) exists. The analysis of expressed sequence tags (EST) is an efficient and easy approach for gene discovery as well as for examining gene expression in specific tissues in a qualitative and quantitative way. Here we describe the constructions and quality analysis of in total thirteen cDNA libraries, nine infected with V.
modify with temperature the normal way of sex differentiation during embryogenesis in O. niloticus, before the onset of the gonadogenesis. XX males and females were used to produce XX progenies (n = 4). Shortly after fertilization (b 12 h), eggs were removed from the mouth of the female and were incubated at 27 ° C (control group), 34, 35 and 36 °C during the embryonic development. Experimental temperature was reached within 3 h, and was cool down at 30 °C within 24 h after hatching. At the age of 2 months (MBW = 3 g), sex ratios were determined with the acetocarmin squash method. Sex ratios of the control group were 100% females whereas a significant proportion of males (mean: 10.3, 17.9 and 20.0% at 34, 35 and 36 °C respectively) appeared in treated groups. These results prove that the normal way of sex differentiation could be modified before the onset of gonadogenesis, the temperature acting directly on the brain probably by inhibiting the expression of the gene coding for the brain aromatase. These results could confirm the role of the brain in the sex differentiation process and allow us to hypothesize for the first time on the “sexualisation” of the brain in tilapia. doi:10.1016/j.aquaculture.2007.07.176
QTL analysis for spawning date in ayu (Plecoglossus altivelis) on three-generation family T. Sakamoto a, H. Koshio a, M. Okochi a, Y. Watababe b, H. Hara b, H. Aikawa b, H. Fukuda a, N. Okamoto a a Department of Marine Biosciences, Faculty of Marine Science, Tokyo University of Marine Science and Technology, Tokyo, Japan b Kanagawa Prefecture Fisheries Research Institute, Kanagawa, Japan Construction of a genetic map based on DNA markers at a large number of sites in the fish genome is necessary to identify quantitative trait loci (QTL) controlling traits of economic importance to aquaculture (e.g. disease resistance, growth and spawning time). To search for QTL associated with spawning date in Ayu (Plecoglossus altivelis), we have constructed a genetic linkage map using 163 microsatellite markers. In the previous study, we have mapped fifteen QTL markers for spawning date representing six linkage groups in a backcross family produced by crossing two stains that differ in spawning date. Four of these QTL markers located on two linkage groups showed significant association with spawning date in another backcross
S307
families. In this study, we have performed QTL analysis on three-generation family to track the linkage between a trait and markers through next generations. We have mapped newly seven QTL markers for spawning date representing 4 linkage groups in the backcross family. Total nine QTL markers (two QTL markers in previous study) were analyzed on next generations. Two of these QTL markers located on two linkage groups have shown significant association with spawning date on second-generation family. One of these QTL markers has demonstrated significant association on third-generation family. These results suggest that this trait is polygenic, and these QTL markers could be possible to use for marker-assisted selection. doi:10.1016/j.aquaculture.2007.07.177
Markers and methods for detecting introgression on hybridised populations N. Sanz, R.M. Araguas, R. Fernandez, M. Vera, J.L. Garcia Marin Girona University, Biology, Campus Montilivi, 17071 Girona, Spain Many years of hybridization between native and cultivated individuals of Salmo trutta in the Iberian Peninsula, have led to different levels of hatchery introgression in natural populations. For many years, allozymes data and complete mtDNA control region sequences have been used to analyze the ongoing processes of human mediated hybridization. More recently, the appearance of higher polymorphic genetic markers (microsatellites) and new statistical approaches (Bayesian-based methods) have provided new tools to improve the evaluation of these introgression processes. We assess the effectiveness of three modelbased Bayesian methods (Structure, Newhybrids and Geneclass) in nine wild samples of S. trutta from the Iberian Peninsula using allozymes and microsatellites markers to detect hatchery introgression. Additional data from mtDNA have also been included in order to compare introgression estimates obtained by nuclear and mitochondrial markers. Results showed the importance of considering a large number of genetic markers and methods to evaluate introgression accurately. Implications of these results to decide what to conserve and which is the best policy to avoid the extinction of the remaining native populations are also
S308
Abstracts / Aquaculture 272S1 (2007) S238–S321
discussed. Keywords: Allozyme, Assignment test, Brown trout, Introgression, Microsatellite, mtDNA. doi:10.1016/j.aquaculture.2007.07.178
A gene-based radiation hybrid map of the gilthead sea bream Sparus aurata E. Sarropoulou a, G. Kotoulas a , L. Bargelloni b, D.M. Power c, R. Franch b, B. Louro c, A. Magoulas a, T. Patarnello f, F. Senger d, F. Galibert d, R. Geisler e a Institute of Marine Biology of Crete, Department of Genetics and Molecular Biotechnology, P.O. Box 2214, 710 03 Iraklio, Crete, Greece b Universita di Padova, Dipartimento di Sanita Pubblica, Patologia Comparata e Igiene Veterinaria, 35020 Legnaro, Italy c Center for Marine Science-CCMar, Universidade do Algarve, 8000-117 Faro, Portugal d UMR6061 CNRS, Genetique et Developpement, Faculte de Medecine, 35043 Rennes Cedex, France e Max-Planck-Institut fuer Entwicklungsbiologie, Abt. IIIGenetik, Spemannstrasse 35, 72076 Tuebingen, Germany f Department of Biology, University of Padova, via G. Colombo 3, 35131 Padova, Italy Comparative genomics is very promising for retrieving genomic information from fully sequenced model species to non-model species of high economic importance and/or species interesting from a biological or evolutionary aspect. One powerful method that allows comparative genome analysis has been shown to be comparative mapping. For teleosts of commercial interest genomic tools and resources facilitating comparative studies are under development. Among different mapping methods the radiation hybrid mapping results in dense and reliable genome maps for comparative use, since unlike linkage mapping, it permits to map coding regions as easily as neutral markers. In this study we present a first approach to comparative genomics by radiation hybrid mapping of the gilthead sea bream Sparus aurata, a non-model fish species of commercial and evolutionary interest, as representing the worldwide distributed species rich family of Sparidae, within the Perciformes. We were able to map 516 gene-based markers appropriate for comparative mapping studies. Data analysis has highlighted synteny conservation and similarity of gene order of sea bream to extensive studied model fish species like zebrafish, medaka, fugu and tetraodon and revealed evolutionary conserved regions and regions where
breakpoints occurred. Furthermore useful insights and tools for selective breeding came from the integration of the RH map with a linkage map, based on microsatellite markers that have been mapped on both. This genebased anchoring of radiation hybrid map on model species pinpoints to polymorphic microsatellite markers mapping near genes of interest as priority ones for QTL mapping and marker assisted selection. doi:10.1016/j.aquaculture.2007.07.179
Analysis and characterization of genes involved in immune functions isolated from the gilthead sea bream Sparus aurata and the European sea bass Dicentrarchus labrax infected with Vibrio anguillarum or nodavirus E. Sarropoulou a, P. Sepulcreb b, V. Mulero b, J. Meseguer b, L. Poisa c, S. Dios c, A. Figueras c, B. Novoa c, V. Terzoglou a, M. Kube d, R. Reinhardt d, G. Kotoulas a a Institute of Marine Biology of Crete, Department of Genetics and Molecular Biotechnology, P.O. Box 2214, 710 03 Iraklio, Crete, Greece b Department of Cell Biology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain c Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Científicas-CSIC. Eduardo Cabello, 6. 36208, Vigo, Spain d Max-Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin-Dahlem, Germany The gilthead sea bream (Sparus aurata) and the European sea bass (Dicentrachus labrax) are species of the main European aquaculture products and therefore prospective model species for the Perciformes, which includes several other commercially important species. Analysis of genes involved in immune functions contributes to gene expression studies, isolation of biomarkers as well as to the development of molecular resources for functional genomics. Although gene resources in marine fish species increase rapidly they lag behind those of other agricultural animals and only scanty information about the genetic source of phenotypic variation and the identity of quantitative trait loci (QTL) exists. The analysis of expressed sequence tags (EST) is an efficient and easy approach for gene discovery as well as for examining gene expression in specific tissues in a qualitative and quantitative way. Here we describe the constructions and quality analysis of in total thirteen cDNA libraries, nine infected with V.