- E.Coli, a bacterium
- C.Elegans, a simple nematode (worm) with 1031 cells
- Drosophilia, fruit flies
- Laboratory mice
These organisms are very well known and are possibly even more known than humans. They can be bred quickly. We know their genetic lines perfectly, you can order some with specific mutations activated.
It is not necessary optimal picks, there is a lot of history behind these choices. The thing is, if you want to check an effect on a real organism, we know very well how these normally react so spotting small variations in growth, metabolism or behavior is easy. They are the benchmarks of biology.
You found a molecule that kills cancer cells? Congratulations! Check first that it does not harm E.coli normal metabolism. Check it works on C.Elegans, make sure that fruit flies are still fertile, fly normally, etc...
> 60% DNA shared with humans + 4 chromesomes for easy mutation tracking + 2 week reproductive cycle for fast generation studying + easy to house/keep alive = great lab specimens to test genetic mutations
In addition to that:
* Some chromosomes, the ones in the salivary gland of the drosophila melanogaster are huge. Much easier to study under the microscope.
* Most important being the very short mutation cycle: 10 days.
* Very easy to see mutated phenotypes. 4 chromosomes -> eye color, wing size, ...
There were very good reasons Meigen 1830 and Castle 1901 picked them from the very beginning on.
The article didn't even get the most basic numbers right. It were 8 nobel prizes so far based on drosophila research, not 6.
1. Morgan 33
2. Müller 46
3. Beadle, Tatum 56
4. Delbrück, Hershey, Luria 69
5. Lewis, Nusslein-Volhard, Wieschaus 95
6. Axel, Buck 04
7. Hoffman, Beutler, Steinmann 11
8. Hall, Rosbash, Young 17
But, unless this has changed recently, impossible to preserve without housing them and keeping them alive. You can freeze cell lines, nematode worms, and vertebrate sperm and eggs, but there's no analogous technique for fruitflies. Once you've made a useful mutant, if you want to keep it, some poor graduate student is going to have to keep flipping those flies forever.
It's striking how useful they were when we really new very little about how the information of life was encoded and how they continue to be a powerful and relevant model system for studying more complex aspects of biology, such as the brain e.g. https://www.janelia.org/lab/rubin-lab .
1. When genetic mapping was expensive, they were some of the first mapped.
2. They procreate quickly. Faster reproduction cycles means quicker experiments.
3. Because they were some of the first, more biologists have more experiments with these genomes. So faster and more advanced work can commence.
4. Nobody complains about experiments with what effectively amounts to insects and minnows (yes, I know zebrafish aren't - im going after the sentiment here).
Actually, they are part of the minnow family (Cyprinidae). Some, restrict it to smaller fish in the subfamily Leuciscinae, but there is no single minnow species/genus making the term somewhat ambiguous.
Similarities are easier to see once you realize that all organisms (including us) are just a bunch of cells who decided to stick together.
― Jacques Monod