Most insights into human disease are a result of experiments that would be unethical or unfeasible to perform on humans. Instead we can use models to look at the functions of genes involved in maintaining healthy organisms in order to obtain vital clues about the causes and progression of human diseases.
Most people are familiar with the use of mice and rats as model organisms (lab rats!) As mammals they are fairly similar to humans; therefore they can be used to study complicated processes underlying normal human development and disease.
Often we want to know something simple that is likely to occur in all living organisms – in which case scientists will use a basic pokie games organism such as bacteria or yeast as they’re easy and cheap to look after and they’re very well understood. Sometimes they can be too simple - as you can imagine it’s difficult to look at how eyes form in something that doesn’t have any!
A simple multicellular organism that is used as a automaty online model by scientists all over the world is the microscopic worm C. elegans. There are just 1031 cells in the adult, which makes understanding how the animal develops much easier. It is so simple that we know where every single one of its 302 neurons connects with each other, something that is impossible to do with the estimated 100 billion neurons in the human brain!
Zebrafish are vertebrates and have similar body plans (and similar tissues and organs) to humans, but they're much easier and cheaper to look after then mice and rats. They have lots of other advantages over other model organisms.
Click here to learn more about the advantages of zebrafish.