Cynically Optimistic

There's been a lot of concern lately about genetically modified plants and animals, and their possible effects on the human food supply. A lot of the genetic modifications make certain plants disease resistant or produce more fruit. The concern is that these modifications will somehow adversely affect humans or other animal species due to a competitive advantage. This is a very broad topic, and I might try to tackle it a bit more in the future, but for now I'd like to bring your attention to one little fish - the zebrafish (Danio rerio).

The zebrafish is native only to the Ganges River in India. It is a small fish, common in fishtanks throughout the world, and usually striped black and grey. The zebrafish is commonly used throughout the scientific world as a genetic model because females lay hundreds of eggs which are fertilized externally, and the developing embryos are clear so that their development is easily observed. Best of all, a hatched egg develops into a tiny fish after only 24 hours (and only takes 2-4 days after fertilization to hatch). This makes the zebrafish an excellent tool to follow genetics and DNA mutation. Compare this to the common fruit fly (which is not a vertebrate model) that has much faster development (a few hours) or the common lab mouse, in which embryos take 21 days to develop.

Researchers have used the Zebrafish to study many different development pathways and protein functions. One of the common techniques used today to study specific proteins is to attach a fluorescent protein to a protein of interest. To do this, they inject the embryos before they hatch with a gene for the red fluorescent protein. Researchers at the National University of Singapore initially engineered the fish to express this protein to study pollution in lakes and rivers.

A company called Yorktown Technologies in Austin, TX, has decided that these fluorescent-red Zebrafish would look wonderful in fish tanks and have decided to sell them under the name GloFish. The state of California has restricted the sale of these fish, but they are available for everyone for around $5.00. The FDA recently approved the sale of these fish because they are not used for food purposes and pose no threat to the food supply. So, if you own a freshwater fish tank and want a cool fish that will glow under a black light, head to your local tropical fish store.