cells. Organisms produced from the reproductive cells with these newly introduced
genes would be transgenic in the following generation.
F. Producing Beneficial Materials (Cell Breeding)
Examples of obtaining useful materials through culturing of somewhat specialized fish or shellfish cells include the secretion of a nacreous layer in oyster
mantle cells and the production of maturity inducing substances in the follicle cells
of starfish ovaries. For fish, experiments have been conducted to produce peptide
hormones through culturing of pituitary gland cells. More possibilities exist besides
these. It would also be beneficial not simply to take advantage of secretion cells that
have undergone specialization, but to fuse them with cells from tumors such as
myelomas to produce hybrid cells with reproduction capabilities, which could then
be cultured for the effective production of useful substances. Possibilities are also
emerging for the use of hybridomas from mouse lymphocytes to produce monoclonal antibodies for specific fish antigen proteins, which could be used for clinical
testing and research (Oshiro 1990).
4.4 Gene Manipulation
At root, breeding is a matter of assembling genes that are beneficial to humans
within a particular organism or population. The traditional approach of selection
and cross-breeding and the techniques used to date for chromosome and cell
manipulation follow a somewhat general breeding approach of simply assembling
chromosomes (the “cassette tape”) or chromosome sets (O X cassette collections)
that have the target genes. As a result, the collection comes to include songs that are
unnecessary or even undesirable in addition to the desired ones. In contrast, gene
manipulation, or the extraction of only the desired genes for introduction into the
genome of a fish that one is seeking to improve, could be considered the equivalent
of selecting the songs one likes and copying them to or splicing together a master
tape. The resulting fish with new genes introduced are called transgenic fish, or
simply hosts (Old and Primrose 1981).
In the natural world, regulation of expression (as with the puff observed in the
fruit fly’s saliva chromosome, where a puff is a discontinuously swollen structure
observed in specific parts of a multi-stranded chromosome), amplification (as with
ribosome RNA genes during the formation of fish and amphibian eggs), recombination (as with the reconstitution of antibody genes in lymphocytes), and transfer
(as with transposons and transposable elements) at the level of the single gene occur
frequently and are often essential to survival.
Artificial gene manipulation began in 1944 with Avery et al., who transferred
DNA extracted from the S variety of pathogenic Streptococcus pneumoniae through
culturing of bacteria from the non-toxic R variety. Transformation through introduction of such DNA fragments (genes) has already been performed successfully in
several species, including higher-order plants and animals. As various more genes
96
4 Fish Breeding and Biotechnology
genes would be transgenic in the following generation.
F. Producing Beneficial Materials (Cell Breeding)
Examples of obtaining useful materials through culturing of somewhat specialized fish or shellfish cells include the secretion of a nacreous layer in oyster
mantle cells and the production of maturity inducing substances in the follicle cells
of starfish ovaries. For fish, experiments have been conducted to produce peptide
hormones through culturing of pituitary gland cells. More possibilities exist besides
these. It would also be beneficial not simply to take advantage of secretion cells that
have undergone specialization, but to fuse them with cells from tumors such as
myelomas to produce hybrid cells with reproduction capabilities, which could then
be cultured for the effective production of useful substances. Possibilities are also
emerging for the use of hybridomas from mouse lymphocytes to produce monoclonal antibodies for specific fish antigen proteins, which could be used for clinical
testing and research (Oshiro 1990).
4.4 Gene Manipulation
At root, breeding is a matter of assembling genes that are beneficial to humans
within a particular organism or population. The traditional approach of selection
and cross-breeding and the techniques used to date for chromosome and cell
manipulation follow a somewhat general breeding approach of simply assembling
chromosomes (the “cassette tape”) or chromosome sets (O X cassette collections)
that have the target genes. As a result, the collection comes to include songs that are
unnecessary or even undesirable in addition to the desired ones. In contrast, gene
manipulation, or the extraction of only the desired genes for introduction into the
genome of a fish that one is seeking to improve, could be considered the equivalent
of selecting the songs one likes and copying them to or splicing together a master
tape. The resulting fish with new genes introduced are called transgenic fish, or
simply hosts (Old and Primrose 1981).
In the natural world, regulation of expression (as with the puff observed in the
fruit fly’s saliva chromosome, where a puff is a discontinuously swollen structure
observed in specific parts of a multi-stranded chromosome), amplification (as with
ribosome RNA genes during the formation of fish and amphibian eggs), recombination (as with the reconstitution of antibody genes in lymphocytes), and transfer
(as with transposons and transposable elements) at the level of the single gene occur
frequently and are often essential to survival.
Artificial gene manipulation began in 1944 with Avery et al., who transferred
DNA extracted from the S variety of pathogenic Streptococcus pneumoniae through
culturing of bacteria from the non-toxic R variety. Transformation through introduction of such DNA fragments (genes) has already been performed successfully in
several species, including higher-order plants and animals. As various more genes
96
4 Fish Breeding and Biotechnology