So what really defines something as a model organism?

[Genecks]

I often wonder this question, because I am starting to find organisms that I think should be model organisms. I'm not going into detail, as I might actually use such an organism to do a graduate thesis, but still... I'm surprised that for some species when they have such fascinating phenotypic aspects, they are not used for scientific research.

 

For instance, why zebrafish? Why not some other kind of fish that might have outstanding phenotypic charactistics that make it a prime topic for study? Why have people compiled so much literature on just zebrafish?

 

So what really defines something as a model organism?

[CharonY]

Prerequisites are

a) provides traits useful for the intended types of study and are representative

b) already is well characterized (e.g. sequenced or physiological data is readily available)

c) can be easily maintained under laboratory conditions

d) is already in used by a number of groups/consortia (usually a consequence of b)

e) also allows extrapolation to other models/organisms (see also a)

 

Zebrafishes have been extensively used in toxicological studies and are in particular useful in analyzing the effects of toxicants on early development.

 

In fact, having outstanding, unique traits often makes and organism less useful as a model (with few exceptions).

Edited June 4, 2010 by CharonY

[Greippi]

Often it just so happens that way. For example, there's nothing special about E. coil, sure it has many useful qualities for being used as a model organism but it's pretty much chance as to why it's become the most studied bacterium.

[CharonY]

Not purely chance. At that date it was one of the easiest bacterium to be propagated in the lab with low generation time and genetic accessibility. Not too many bacteria can compete with that. Also keep in mind that the technical repertoire was less varied than nowadays.

 

But yes, after a few labs started out with that it eventually became established- essentially it started off with point a and c, followed by b and d.

[Greippi]

Edit button's disappeared so I'll say I did, of course, mean E. coli not E. coil there!

 

Xenopus laevis is used as a model organism because it has a "very manipulable embryo" and is useful in developmental biology.

 

It can also swallow its own head and skull by curving its lips around its head and sucking. But that hasn't been found to be useful to science yet.

[Blahah]

The zebrafish is an ideal model organism because is it seethrough - allowing very easy study of organ development in living organisms.

 

You can't just decide on a new model organism yourself, and there's certainly no point in keeping it secret. For it to be model, many groups must be working on it.

 

CharonY's criteria are spot on.