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Divergent selection for growth within one self-fertilized line of bay scallop Argopecten irradians irradians Lamarck (1819)
S320
Abstracts / Aquaculture 272S1 (2007) S238–S321
10.48% and − 3.07% to 3.36% respectively. A superior cross AB was constructed, which displayed significant heterosis for fertilization, hatching, metamorphosis and growth. It was concluded that selectively crossbreeding of Pacific abalone populations could be advantageous in the farming.
Structure and function of fatty acyl desaturase genes in Atlantic salmon (Salmo salar L.) and Atlantic cod (Gadus morhua L.) X. Zheng, K. Bartie, D.R. Tocher, A.J. Teale Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, United Kingdom
doi:10.1016/j.aquaculture.2007.07.205
Divergent selection for growth within one self-fertilized line of bay scallop Argopecten irradians irradians Lamarck (1819) G. Zhang a, H. Zheng a, X. Liu a , X. Guo b a Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China b Haskin Shellfish Research Laboratory, Institute of Marine and Coastal Sciences, Rutgers University, Port Norris, NJ 08349, USA To precisely estimate realized heritability for predicting response to selection and determine if mass selection can be carried out within a self-fertilization line, divergent selection for growth in the bay scallop Argopecten irradians irradians was conducted in 2004 using a self-fertilization line produced in 2003. Mass selection for design on the basis of a self-fertilized line in bay scallop is as effective as that on the basis of a stock. From 13 days larvae to 160 days adults, differences among upward selected for faster growth, control, and downward selected for slower lines, were clearly significant (Upward N Control N Downward), although effect of selection was not exhibited to larvae from day 1 to day 7 due to effect of egg origin. Standardized responses to selection (SR), realized heritability (hR2) and genetic gains (GG) were 0.432, 0.251, and 9.98% in the upward direction and 0.284, 0.165, and 7.05% in the downward direction, respectively, which are significantly different in opposite direction, in spite of the same selection intensity applied in the two directions. Difference in two directions for SR, hR2, and GG was 0.148, 0.086, and 2.93%; respectively, and a significantly asymmetrical response was generated by divergent selection. However, SR and hR2 for design base on a line were significantly smaller than those based on a stock due to genetic drift and inbreeding depression. doi:10.1016/j.aquaculture.2007.07.206
Fish are an important source of the n-3 highly unsaturated fatty acids (HUFA), the synthesis of which involves enzyme-mediated desaturation. A Δ6 fatty acyl desaturase cDNA has been cloned from Atlantic cod and functionally characterized recently in our laboratory. Various attempts to clone further desaturases from cod have so far failed to reveal a distinct Δ5 desaturase gene. Here we compare the function and genomic structure of the cod Δ6 gene with that of Atlantic salmon (Salmo salar) Δ6 and Δ5 fatty acyl desaturase genes. The cod Δ6 desaturase cDNA (mRNA) includes an openreading frame (ORF) of 1344 bp, which specifies a protein of 447 amino acids (GenBank accession no. DQ054840). However, the salmon Δ6 and Δ5 desaturase cDNAs both contain 1365 bp of ORF encoding 454 amino acid residues. The amino acid sequence predicted by the cod Δ6 desaturase ORF shows 75% and 76% identity to the salmon Δ6 and Δ5 desaturases, respectively. All ORFs include the characteristic features of microsomal fatty acid desaturases, including two transmembrane regions, three histidine boxes and an N-terminal cytochrome b5 domain containing the haembinding motif, HPGG. Screening and sequence analysis of the genomic DNA of a single fish revealed that all three desaturase genes comprised 13 exons. The cod and salmon Δ6 desaturase genes spanned 5031 bp and 7965 bp of genomic DNA, respectively. These findings provide further insight into the pathway of HUFA biosynthesis in marine fish and contribute to ongoing investigation of the mechanisms of control and regulation of HUFA synthesis. doi:10.1016/j.aquaculture.2007.07.207
Inbreeding depression for various traits in two stocks of the bay scallop, Argopecten irradians irradians Lamarck (1819) H. Zheng a, G. Zhang a, X. Liu a, X. Guo b a Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China b Haskin Shellfish Research Laboratory, Institute of
Abstracts / Aquaculture 272S1 (2007) S238–S321
10.48% and − 3.07% to 3.36% respectively. A superior cross AB was constructed, which displayed significant heterosis for fertilization, hatching, metamorphosis and growth. It was concluded that selectively crossbreeding of Pacific abalone populations could be advantageous in the farming.
Structure and function of fatty acyl desaturase genes in Atlantic salmon (Salmo salar L.) and Atlantic cod (Gadus morhua L.) X. Zheng, K. Bartie, D.R. Tocher, A.J. Teale Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, United Kingdom
doi:10.1016/j.aquaculture.2007.07.205
Divergent selection for growth within one self-fertilized line of bay scallop Argopecten irradians irradians Lamarck (1819) G. Zhang a, H. Zheng a, X. Liu a , X. Guo b a Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China b Haskin Shellfish Research Laboratory, Institute of Marine and Coastal Sciences, Rutgers University, Port Norris, NJ 08349, USA To precisely estimate realized heritability for predicting response to selection and determine if mass selection can be carried out within a self-fertilization line, divergent selection for growth in the bay scallop Argopecten irradians irradians was conducted in 2004 using a self-fertilization line produced in 2003. Mass selection for design on the basis of a self-fertilized line in bay scallop is as effective as that on the basis of a stock. From 13 days larvae to 160 days adults, differences among upward selected for faster growth, control, and downward selected for slower lines, were clearly significant (Upward N Control N Downward), although effect of selection was not exhibited to larvae from day 1 to day 7 due to effect of egg origin. Standardized responses to selection (SR), realized heritability (hR2) and genetic gains (GG) were 0.432, 0.251, and 9.98% in the upward direction and 0.284, 0.165, and 7.05% in the downward direction, respectively, which are significantly different in opposite direction, in spite of the same selection intensity applied in the two directions. Difference in two directions for SR, hR2, and GG was 0.148, 0.086, and 2.93%; respectively, and a significantly asymmetrical response was generated by divergent selection. However, SR and hR2 for design base on a line were significantly smaller than those based on a stock due to genetic drift and inbreeding depression. doi:10.1016/j.aquaculture.2007.07.206
Fish are an important source of the n-3 highly unsaturated fatty acids (HUFA), the synthesis of which involves enzyme-mediated desaturation. A Δ6 fatty acyl desaturase cDNA has been cloned from Atlantic cod and functionally characterized recently in our laboratory. Various attempts to clone further desaturases from cod have so far failed to reveal a distinct Δ5 desaturase gene. Here we compare the function and genomic structure of the cod Δ6 gene with that of Atlantic salmon (Salmo salar) Δ6 and Δ5 fatty acyl desaturase genes. The cod Δ6 desaturase cDNA (mRNA) includes an openreading frame (ORF) of 1344 bp, which specifies a protein of 447 amino acids (GenBank accession no. DQ054840). However, the salmon Δ6 and Δ5 desaturase cDNAs both contain 1365 bp of ORF encoding 454 amino acid residues. The amino acid sequence predicted by the cod Δ6 desaturase ORF shows 75% and 76% identity to the salmon Δ6 and Δ5 desaturases, respectively. All ORFs include the characteristic features of microsomal fatty acid desaturases, including two transmembrane regions, three histidine boxes and an N-terminal cytochrome b5 domain containing the haembinding motif, HPGG. Screening and sequence analysis of the genomic DNA of a single fish revealed that all three desaturase genes comprised 13 exons. The cod and salmon Δ6 desaturase genes spanned 5031 bp and 7965 bp of genomic DNA, respectively. These findings provide further insight into the pathway of HUFA biosynthesis in marine fish and contribute to ongoing investigation of the mechanisms of control and regulation of HUFA synthesis. doi:10.1016/j.aquaculture.2007.07.207
Inbreeding depression for various traits in two stocks of the bay scallop, Argopecten irradians irradians Lamarck (1819) H. Zheng a, G. Zhang a, X. Liu a, X. Guo b a Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China b Haskin Shellfish Research Laboratory, Institute of