Welcome to the section on Micronaut.ch which explores, analyzes and explains fascinating microscopical structures.
The genome is one of the most powerful entities in the body of living organisms. If some parts of it are broken, things can go wrong. No other creature shows this better than the fruit fly.
The fruit fly, Drosophila melanogaster, is one of the most important scientific experimental animals in the world. Without it, we would not know anything about the diversity of genes, or how a complex organism arises from an egg within a few weeks, or what effect gene mutations can have on this process.
The fruit fly offers a wonderful opportunity to investigate these processes, for it brings the hidden world of the genes to the surface like no other life form. Most mutations have a dramatic effect on their behaviour or appearance. Changes in a single gene can cause the wings to be crippled or entirely missing, the antennas to be fused together, or the skin to appear white.
Thousands of such genetically determined deviations from the norm were discovered in the last hundred years. The fly on the left hand side has a very serious damage. Its two eyes are missing. Researchers have become aware of this mutation twenty years ago. In the course of their studies, they have identified a gene that is primarily responsible for the development of the eye and baptized it “eyeless” (because it was discovered in an eyeless fly). If it is broken or if it mutated to something else, the animals grow no eyes during their transformation from maggot to fly.
“eyeless” is a very powerful gene as it turned out. The fly on the right hand side demonstrates this. It has two normal eyes on its head plus one extra eye on each of its two antennas and on each front leg. This fly does not appear in nature. Instead, it was bread in the laboratory.
The researchers have transferred the “eyeless” gene to the part of the fly larva which will later during metamorphosis develop into the front legs and the antennas. Usually it does not occur there, but once placed there the fly grows fully functional eyes. However, they are not a benefit for survival, because with extra eyes on legs walking becomes quite difficult. Thus, in nature this type of fly would soon die out.
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