Table 1.

Advantages of model organisms compared to the mouse.

	Mouse	Zebrafish	Drosophila	C. elegans
Generation time	10 weeks	4–8 weeks	12 days	3 days
Numer of offspring	6–8 pups/2 months	200 eggs/week	120 eggs/day	140 eggs/day
Lifespan	2–3 years	2–3 years	40–50 days	14–21 days
Regulatory and ethics constraints	yes	no	no	no
Expense of housing	high	moderate	low	low
Number of neurons	> 70,000,000	~ 10,000,000	> 100,000	302
Fully annotated genome	yes	In progress/duplicate genes	yes	yes
Availability of mutants and transgenics	yes	growing	yes	yes
Homolgy with humans	> 90%	84%	77%	65%
Easy behavioral assays	no	yes	yes	yes
High throughput screening	no	yes	yes	yes