Genetic requirement for transgenic fish development

1. Genetic requirement
for transgenic fish
development
Group members
Rameen 25
Hina 4
Syeda iqra 5
Mahnoor 2
Maleeha 6
Date : 17th
may 2016

2.  An organism that has a foreign or modified
gene transferred to its genome using the in
vitro genetic techniques is called a
genetically modified organism (GMO) or a
transgenic organism.
 Transgenes can originate from
phylogenetically distant organisms or from
the same species.

4.  First transgene fish was developed in 1980’s.
 For the production of transgenic animal, a cloned gene
is transferred into the fertilized egg before the
completion of first cleavage.
 Scientists are seeking ways to genetically engineer fish
and other seafood species to introduce or amplify
economically valuable traits.
 Fish are of particular interest to researchers since
many fish produce large quantities of eggs; those eggs,
being external to the animal, make it relatively simple to
insert novel DNA

5.  Research on transgenic fish is currently under development
for at least 35 species of fish worldwide, as well as for a
variety of mollusks, crustaceans, plants, and marine
microorganisms, for various purposes.
Uses:
 Transgenic technology has been successfully used to
develop fast-growing super-fish stocks for
 human consumption
 to produce pharmaceuticals
 to test water contamination in both developed and
developing countries.
 Several laboratories now have GM fish with increased
growth performance caused by extra copies of GH genes
(growth hormones genes)

6. A. Selection of species and genes
 For the aquacultural importance, Common carp,
Channel catfish, Chinese carps, Salmon, Trout
and Tilapia are the best species for the
transgenic project.
 Improvement of growth rate, imparting
disease and environmental stress resistance
are some important traits for transgenesis.

7. B. Reporter genes
 a gene whose products detects or marks the cells,
tissues, organisms that express the gene from those
that do not. used as an indication of whether a certain
gene has been taken up by or expressed in the cell or
organism population.
 Reporter genes isolated from prokaryotes, E. coli, are
used in fishes- ie lac Z gene, Cat gene .
 Recently luciferase and green fluorescent protein are
used.
 Ornamental GloFish have different fluorescent colors.
They are available as a pet

8. GloFish

9. C. Genes of interest
1. Growth hormone gene
‘Growth hormone’ (GH) is produced by the anterior lobe
of the pituitary plays the key role.
 It increases growth by stimulating, appetite and cell
reproduction
 protein hormone
 molecular weight of about 22 kD
 Transgenic fish carrying GH gene will produce growth
hormone endogenously bypassing the necessity of
exogenous hormone treatment.
 GH gene has been cloned in some fishes either from
the genomic library or from the cDNA library.

10. Salmon/trout can grow up to 6 times faster than wild-type
fish because they have extra copies of Growth Hormone
(GH) gene.

11. 2. Antifreeze protein genes
 Production of cold resistant fish variety is useful for
establishing aquaculture industry in the temperate
region, where water gets frozen during winter.
 The gene responsible for imparting cold resistance was
cloned from winter flounder (Pseudopleuronectes
americanus), which lives in the polar sea.
 This species avoids freezing of its blood even at –7°C
temperatures by producing a set of anti-freeze proteins
(AFP).
 AFP are produced in the liver and exported to the blood
stream.
C. Genes of interest

12. 3. Disease resistance
Fish has poorly developed antibody dependent
immunity.
Efforts to produce disease resistance in fish stocks by
transgenesis have begun recently.
The potential of Rainbow trout lysozyme gene as a
bacterial inhibitor was assessed in Atlantic salmon.
C. Genes of interest

13. E. Detection of transgene
 There are various ways and means to detect this.
 Most of them used southern blot and northern blot to
detect the transgenes using a suitable probe.

14. Food safety of transgenic (GM)
fish
 GM food safety depends on the nature of the gene,
the transgene product it encodes and the resulting
phenotype.
 Transgenic fish have received extra copies of GH
genes, resulting in only moderately raised levels of
circulating GH.
 GH is a protein hormone which is degraded along with
all other food protein.

15.  Meat from fish modified with GH is regarded
as completely safe for human consumption
Concerns have been voiced of the possible risks
of consumption of transgenes,
 their resulting protein,
 potential production of toxins by aquatic
transgenic organisms,
 changes in the nutritional composition of
foods.

16. Environmental impact of transgenic fish
 The possible impacts from the escape of GM
organisms from aquaculture facilities are of great
concern to some scientists and environmental groups.
 Escaped transgenic fish could harm wild fish through
increased competition or predation.
 The consequences of such competition would depend
on many factors, including the size of the wild
population, the number and specific genetic strain of
the escaped fish, and local environmental conditions.