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Rebecca Huh

on 12 March 2014

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Transcript of Glofish

1) GloFish could threaten natural species
2) Population control
3) Effect on other species
4) Ethnic issue
5) The nature of GMO
What is a Glofish?
Why Zebrafish?
1) They are small in size, therefore they can
be kept in a large amount.
2) They reproduce in large amount. A single
pair of parents can lay 100-200 eggs in a
single spawning.
3) They are vertebrates, therefore genetic
control of their development and of genetic
diseases is similar to humans
4) They are cheaper than monkeys and mice
5) Zebrafish embryos are translucent, making it easy to identify mutants with abnormal development

) Use in biology labs:
Some biologists used Glofish to carry out analysis of Mendelian inheritance patterns. These protocols help them to analyze up to three genes and four inheritance patterns in the same cross.
argued that because tropical aquarium fish are not used for food purposes, they pose no threat to the food supply.
Economic growth:
Glofish have the potential to foster Salmon population, since they are consumed by Salmon. This will favor fish and pet fish seller.

The first genetically modified pet is
not meant to be eaten,
rather it is available for aquarium
owners under the brand name GloFish

Not all Glofish are fluorescent green
though. There are several gfp gene
constructs, each encoding a
different colored phenotype,
from fluorescent yellow to
fluorescent red.

The green fluorescent protein (GFP) gene
is the section of DNA that encodes for GFP.
GFP is a protein, comprised of 238 amino acids, originally isolated from the jellyfish Aequorea victoria that fluoresces green when exposed to blue light.

GFP in research:
GFP are attached to proteins.
In the case of a protein named MFD,
which is found in peroxisome,
GFP are attached so that
peroxisome could be tracked.
In 1999, Dr. Gong Zhiyuan from the National University of Singapore
developed a glowing zebrafish by extracting Green Fluorescent Protein,
which are responsible for the fluorescent effect from the jellyfish,
and inserted it into the zebrafish.

The original purpose of this modified fish was to detect pollutant in the river.
Their goal was to develop a fish that could detect pollution
by selectively fluorescing in the presence of environmental toxins.
Thus, the heavier the pollution, the brighter the fish will glow

Later, the Yorktown Technologies company bought this technology and market these fishes as pets. They renamed it GloFish. The development of the always fluorescing fish was the first step in this process.
GloFish was developed by inserting GFP protein into the gene of the fish before it hatches from its egg, GloFish will then pass the fluorescence trait along to its offspring upon maturity.
Yorktown technologies justified that GloFish is therefore a breed, not a modified frankenfish, “From that point forward, all subsequent fluorescent fish are the result of traditional breeding”
Terms: Transgene promoter:
A regulatory sequence that will determine at what time the transgene is active
The promoter of GloFish is muscle-specific mylz2 promoter. Reporter (protein coding sequence) is used as a marker gene.

Extracting DNA
- Green Fluorescent Protein (GFP) , which is what makes Jellyfish and coral glows in the dark, are extracted. Such protein are found in every cell of both organisms.
- The protein is isolated from the rest of DNA with restriction enzyme, in a process called mapping.
- The restriction enzymes used to cut out GFP are PstI and XhoI
- After extracting the gene (Typically are those that leave sticky end of the GFP gene) it is copied using DNA polymerase, and then inserted into a E. coli plasmid

Expressing the transgene:
Inserting the gene
Transgenic organisms or genetically modified organisms, are organisms whose genetic material has been altered using the genetic engineering techniques, generally known as recombinant DNA technology.
As soon as the egg is fertilized, the plasmid is
then inserted into the nucleus of the zebrafish’s egg cell through microinjection. The protein thus become a part of the cell’s genome

The GloFish transgene encodes fluorescent reporter proteins that are originally from jellyfish, the Green Fluorescent Protein (GFP) gene, the Red Fluorescent Protein (RFP) gene (from Discosoma striata, striped mushroom) , or the Yellow Fluorescent Protein (YFP) gene (genetic mutant of GFP)

Thus, the muscles of GloFish have a
green, yellow, and red fluorescent
color when activated by strong
light of the correct wavelength.
Under the influence of Zebrafish skeletal
muscle-specific mylz2 promoter, transgenic Zebrafish expressed GFP exclusively in skeletal muscle

However, the mylz2 muscle promoter is so strong that the fish are brightly colored even under normal white light. (Normally, the glowing light is a result of the specific wavelength they absorb in the daylight)
If these fishes escape back to the wild, they might possess a negative impact on the natural species. Like GloFish, GM fish usually have higher disease resistance and better use of nutrients. They could therefore outcompete wild types and affect the balance between predator and prey.
Finally, by mating with wild fish, escaped GM fish could spread the transgene among the wild population, which could cause conflicting effects on mating success, viability in natural habitats and other fitness factors required for the species to survive. GloFish could also occupy new ecological niches where wild species would usually not survive. Finally, by mating with wild fish, escaped GM fish could spread the transgene among the wild population. While Zebrafish are only limited to freshwater, Yorktown Technologies seek to apply this transgenic technology to Barbs, Guppies and even Cichlids.
(Argument against this criticism: The fish have reduced fertility, both because they have been sterilized through pressure treatment while eggs, and when they do reproduce they have fewer offspring. Moreover,research had not directly supported that these “glowing in dark” genetically engineered fish would actually have an advantage over other fish in the wild)

Once GloFish escape into the wild, they have much harder to control and can spread much faster. Gradually, there will be a spreading of the fluorescent coral gene in the native fish
(Argument against this criticism: If GloFish tetras breed with wild black tetras, the fluorescent gene would be passed on for only a limited number of generations)
However, recent evidences show that some species of Glofish is capable of fertilization and will reproduce in a captive environment.
Glofish are small and are easy prey because of the bright colours, and the fact that they glow in the dark without control over that ability. They could foster other species' population by becoming their food.
Can anyone claim rights to nature?
The technology of creating GloFish is owned by scientists working for the Yorktown Technologies. It is not only a type of fish, but a brand and a product under the company of Yorktown Technologies.
Nature itself has created fishes that are red and orange, yet, artificially adding one of these hues to an aquarium resident is immoral. Cough-syrup red or neon yellow are colors that never naturally occurs in the kingdom.

Rebecca Zhang
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