The zebrafish has many characteristics that make it an excellent model organism for studying vertebrate development. But not only in developmental biology, but increasingly in other fields of biomedical research, research with the zebrafish helps to improve diagnostics and therapy of diseases.
The zebrafish, whose zoologically correct name is Danio rerio, belongs to the family of carp-like fish (Cyprinidae). Its striking appearance with dark blue-black longitudinal stripes that offer a zebra-like look gave it its name. The fish, which is quite easy to keep and breed, has enjoyed great popularity as an ornamental fish in aquariums since the beginning of the 20th century.
Originally native to Asia, the fish established itself in the 1990s as an important laboratory animal in biomedical research. The zebrafish is used to research cardiovascular diseases, immunological and developmental biology. But these animals are also used in molecular neurobiology.
The zebrafish as a model organism in biology
Zebrafish are one of the most important animal species in research today after mice. One of the main reasons for this is that the number and type of genes in zebrafish differ far less from mammals and humans than initially thought: around 70 percent of zebrafish genes are also found in humans (source). A whole series of hereditary diseases also show the same appearance in zebrafish and are based on defects in the same genes as in humans. In addition, some human diseases such as skin cancer, leukaemia or Alzheimer's disease can now also be researched.
But it is not only the high genetic similarity to mammals that makes the zebrafish interesting for research. The animals are also extraordinarily fertile. A healthy female can lay up to 700 eggs every fortnight. This is a great advantage for genetic studies such as the mapping of mutated genes, as they usually require a high number of offspring.
As with most bony fish, the entire development of zebrafish, from the fertilised egg to the fully formed larva, takes place outside the mother. In contrast to mice or humans, this process can be observed and, above all, influenced with a microscope. Another great advantage for research is the extraordinary speed of embryonic development in zebrafish: within a few days, a free-swimming larva develops from the egg and has already developed almost all organs. These characteristics make the zebrafish an important experimental animal for developmental biology, as all developmental processes can be observed live from the first cell division to organogenesis.