Researchers have always used bacteria, yeast, worms, fruitflies, fish and rodents in laboratories since experimentation on humans is often unfeasible and presents with an ethical conundrum. These model organisms are chosen depending on the nature and complexity of study and the cost and convenience of its maintenance. Zebrafish (Danio rerio) is today a favourite model organism for various biological research studies for well deserved reasons.
A scientist and fish enthusiast named George Streisinger first used zebrafish for laboratory research since they were readily available in pet shops, easy to rear and conduct experiments upon. In addition, they occupy less space, are easy to transport, have a low feeding cost, breed rapidly with a capacity to lay 100 eggs per week, mature into adults in 3 months and have large see-through embryos that are easy to manipulate. Also, it is easier to simulate their habitat with minimal stress in contrast to rodents, resulting in lesser variation among animals and better experimental data outcome.
Remarkably, a recent zebrafish genome sequencing project by the Sanger Institute, Cambridge highlighted its genome similarity to humans, implying that 70% of overall zebrafish genes and about 84% disease related genes had human analogues conserved through evolution. These studies boosted the value of zebrafish and they are now used for large scale genetic, toxicological and pharmacological screens. The transparent embryos permit the study of morphological changes during growth, development and diseases without sacrificing the animals.
Moreover, the regenerative abilities of the zebrafish have prompted a study to attempt inducing this property in human cells to facilitate faster recovery. It’s also been transported to the International Space Station to study the effect of microgravity on muscle mass and strength. In a decade, this tiny fish has been absolutely pivotal in expanding our comprehension of human physiology, development and disease.