Scientists Modify Zebrafish Germ Line

A discovery by researchers at Purdue University may not sound all that exciting, but it could revolutionize genetic research.

Researcher Paul Collodi and his team developed a technique that allowed them to genetically modify cells they had removed from a zebrafish embryo. When they inserted the modified cells back into the embryo, they demonstrated that the genetic changes they made were present in the zebrafish’s germ line. When the embryo grows into an adult and breeds, the changes in its genome will be passed on to its offspring.

This is an incredible discovery because until now the only animal that germ line changes could be made to was the mouse. But using mice for this sort of research has a number of problems, not the least of which is the cost. The process with mice can end up costing thousands of dollars per mouse.

“With mice you have maybe a dozen embryos to work with,” Purdue’s Paul Collodi told Science Daily, “and you have to do surgery to transplant the embryos back into the mother. Compare that to the zebrafish embryo where we can modify 100 embryos an hour, and, because the embryos develop outside the mother, we don’t have to do surgery. The entire developmental phase takes only four days.”

With a little more refining of the process, genetically modified zebrafish could play a key role in the research that will occupy those studying the human genome — mapping how various genes work to produce specific proteins.

“With the human genome project they’re sequencing genes, and each of those genes causes the body to produce various proteins at different times,” Collodi said. “If you want to understand what the genes actually do, you have to study the function of the proteins they produce, and the zebrafish makes a nice model for that.”

The one hurdle that researchers still have to overcome is finding a way to prolong the length of time they can keep the zebrafish embryo cells in the lab before they have to reinsert them. Currently researchers have only been able to keep the embryo cells alive for a few days. They will need to find a way to keep them alive for several weeks in order to make the sort of genetic modifications that researchers will want to study.


Zebrafish could become genetics “lab rat” of choice. Science Daily, March 6, 2001.

British Activists Harass Fisherman

A 62-year-old disabled angler reported being harassed by about 20 animal rights demonstrators while he attempted to fish on the Granta River in Great Britain. Peter Rainbow told The Daily Telegraph,

I heard some banging of drums and then there were around 20 people carrying baseball bats and pickaxe handles. They were shouting slogans like ‘how many fish have you killed today?’ and ‘how would you like a hook through your mouth?’ … I believe they just wanted to intimidate me. We use barbless hooks and return fish straight to the river. It shows how ill-informed they are.

The demonstrators left after Rainbow called police, and he was not injured.


Hooded activists threaten lone angler. David Sapsted, The Daily Telegraph (UK), March 8, 2001.

Scientists Busy Decoding the Fugu Genome

Animal rights activists like to claim that non-humans are simply too different to serve as models for human beings, but scientists at the Energy Department’s Joint Genome Institute hope that decoding the genome of the fugu, a poisonous fish considered a delicacy in Japan, will yield important clues about how human genes work.

The JGI hopes to have the a preliminary version of the fugu genome finished by spring of 2001. Why the fugu?

“The fugu has a small and compact genome, on the order of a tenth the size of the human genome, and yet whenever researchers have gone into the fugu and looked for human genes, by and large they’ve found them,” Trever Hawkins, director of JGI, told the San Francisco Chronicle.

While the human genome consists of about 3.4 billion different chemical building blocks, the fugu’s genome only has about 400 million different chemical building blocks. Since both fugu and human beings must have had a common ancestor, the working hypothesis is that any genes that the fugu and human beings share in common are likely to be extremely important ones. JGI scientist Paul Predki told the Chronicle, “The intent is to use the fugu sequence as a comparison. We believe it contains essentially the same complement of genes as human DNA.”

Over the next couple decades, medical research is likely to be revolutionized by a knowledge gained by comparing human and non-human genomes combined with the increasingly sophisticated ability to manipulate and modify genes.


Fishing for clues: the genetic map of the lowly fugu could help scientists decipher the human blueprint. Tom Abate, The San Francisco Chronicle, December 11, 2000.

British Researchers to Decode Zebrafish Genome

Now that the human and mouse genomes have been decoded, United Kingdom researchers have announced plans to decode the genome of the zebrafish in a three-year projected funded by the Wellcome Trust medical research charity.

Although mice and monkeys get the lion’s share of press when it comes to medical research with animals, the zebrafish has been an important animal in laboratory studies for a long time. The zebrafish’s blood, kidney, and vision systems are very similar to those in human beings and the species has been used as a model in those areas.

The decoding of the zebrafish genome will help researchers better understand what specific human genes do. The human genome is of limited usefulness by itself, but when scientists can compare the human genome to the genome of mice, zebrafish and others, they will be able to get a very good idea of exactly how the genes interact and how things like inherited diseases arise.

Some zebrafish, for example, suffer from genetic blood disorders that are very similar to human genetic blood disorders. By comparing
the genomes, scientists might get a better understanding of what causes these genetic diseases and how they might be treated.

Currently efforts are underway to decode the genome of dogs and chickens, and some scientists are calling for researchers to focus on decoding the genome of great apes, which are the closest living genetic relatives to human beings.


Zebrafish genome next. The BBC, November 21, 2000.

Research on Sea Squirts Might Aid Infertility Research

Animal rights activists like to claim that medical research on non-humans is pointless since non-humans are too different from human beings. While there are massive differences, which researchers take into account, it is amazing just how much human physiology has in common with something as tiny as the tiny sea squirt. Specifically, the sea squirts reproductive system is very similar to that of human beings and researchers at Newcastle University are hoping that studying the sea squirt might reveal important clues to better understanding human reproduction and, more specifically, some of the causes of infertility.

In this case researchers are examining how the sperm of sea squirts fertilizes eggs. Researchers hope that they will be able to isolate the protein present in the sperm that initiates the fertilization process. Surprisingly there are still very large unknowns about how this process proceeds in human beings.

One of the problems with studying the problem in human beings are legal and ethical issues in experimenting on human eggs and sperm, as well as difficulties in screening human sperm and eggs for any number of diseases that might affect the results of the experiment. “We think we have nicely circumvented all those problems by going after the sea squirt activating factor first,” Dr. Keith Jones told the BBC. “We are hoping that we can identify the factor within a couple of years, and hopefully we can come up with the human equivalent within a matter of months.”


Sea squirts aid fertility research. The BBC, November 23, 2000.

PETA pushing fishing ban, hermit crab ban, deer slaughter ban, and "Monkey Shorts" ban

On July 17 People for the Ethical Treatment of Animals sent Gil the Fish
to lead a protest against fishing in Watertown, New York. In a press release
PETA gushed on about the horrors of fishing. “Fish feel pain — they
have neurochemical systems like humans and sensitive nerve endings in
their lips and mouths. They begin to die slowly of suffocation the moment
they are pulled out of the water.”

As Ingrid Newkirk summed up PETAÂ’s
view, “Animal suffering of any kind is not a sport.” PETA wants
a national ban on fishing enacted.

If it is wrong for fish to
suffer is it okay to shoot bears and birds that might eat fish?

In other PETA-related news

  • PETA urged people to send letters to Sundial Beach and Tennis Resort
    on Sanibal Island, Florida, because an “Ecocenter” there sells
    hermit crabs. According to a PETA release, selling the crabs is “disrespectful
    and ecologically unsound.”

  • PETA demanded Sea Pines, South Carolina, abandon plans to kill 200
    deer who are destroying plants in the area (selling crabs is unsound,
    destroying flora is perfectly acceptable.)

  • In a bizarre twist, PETA wants Turner Broadcasting Systems (TBS)
    to stop running a series of short spots called “Monkey Shorts.”
    The shorts feature chimpanzees and orangutans dressed up as different
    characters who move their lips and move around the screen as a human
    voice over plays. The shorts are shown between TBS feature movies. According
    to PETA, “even the most considerate of trainers cannot compensate
    for the anxiety and frustration of such an unnatural life in captivity.”


Giant “fish” to tackle fishing in Watertown. People for the Ethical Treatment of Animals, Press Release, July 16, 1998.

Help stop the sale of hermit crabs in Florida. People for the Ethical Treatment of Animals, Press Release, July 1998.

Help protest the slaughter of deer at Hilton Head, People for the Ethical Treatment of Animals, Press Release, July 1998.

Urge TBS to cancel ‘Monkey Shorts,’. People for the Ethical Treatment of Animals, Press Release, July 1998.