In defence of the annoying fruit fly a test bed for genetic research

Subject : Science and tech

Section: Biotechnology

Concept :

Thousands of neuroscientists use fruit flies to study learning, memory, sleep, aggression, addiction and neural disorders – not to mention cancer and ageing, processes of development, the gut microbiome, stem cells, muscles and the heart

Diptera

Flies and mosquitoes both belong to Diptera, the group of insects that have only two wings.
The Order Diptera (true flies) includes many common insects such as mosquitoes, midges, sand flies, blowflies and the House Fly.
Most of the insects we see flying around do so with four wings (two pairs), but dipterans (meaning ‘two wings’) use only one pair. The other pair of wings is reduced to club-like structures known as ‘halteres’ that they use for balance.
Common characteristics of the order include:
- One pair of wings (forewings)
- Hindwings reduced to club-like halteres
- A large and moveable head
- Compound eyes that are often very large
- Sucking, piercing and sucking or sponge-like mouthparts (all adapted for a liquid diet)
- The mesothorax (middle segment of the thorax or mid-body) is enlarged, with the prothorax and metathorax small
- Complete metamorphosis, with larvae (maggots) that are always legless, with chewing mouthparts or mouth-hooks, and that often pupate within a hardened case (puparium)

The fruit fly or vinegar fly (Drosophila melanogaster)

The species Drosophila was first mentioned by German entomologist Johann Meigen in 1830 and has since earned a celebrity status among scientists.
It has become the best-understood animal organism on the planet and a powerhouse of modern medical research.
Drosophila melanogaster has been used as a model organism for over a century.
Mutant-based analyses have been used extensively to understand the genetic basis of different cellular processes, including development, neuronal function and diseases.

Helping science

Morgan was not the first to work with Drosophila. But his idea to harness the fly’s cheap husbandry (pieces of banana kept in milk bottles), and rapid reproduction (one generation in about ten days; about 100 eggs per female per day) would make it possible to study evolution in the laboratory.
His mass-breeding experiments with hundreds of thousands of flies led to the discovery of a single fly with white eyes, instead of the red eyes fruit flies normally have. Morgan and his team’s subsequent studies of its white-eyed progeny revealed that genes can mutate and are arranged into orderly and reproducible maps on chromosomes (a long DNA molecule).
It led to an understanding of how genetic disease is inherited.
In the 1940s, scientists, including George Beadle and Edward Tatum, established that some gene codes for proteins can facilitate chemical reactions and produce the molecules needed in cells.
Scientists can study mutant defects, even if the eggs never hatch, which can then inform us about the normal function of the affected gene.
These kinds of genetic studies of Drosophila, combined with emerging technologies, such as gene cloning, helped us understand how gene networks can determine the development of a body and how they can sometimes cause inherited disorders.

A startling likeness

The common ancestor that founded the evolutionary lines of flies and humans, half a billion years ago, appears to have been equipped with biology so well-designed that many of its aspects are still maintained, such as mechanisms of growth or neuronal function.
Because we are so alike genetically, many aspects of human biology and disease have been explored first in Drosophila. Meanwhile, research on fruit flies is fast, cost-effective and extremely versatile. It’s ideal for scientific discoveries.
It is used by neuroscientists for studying learning, memory, sleep, aggression, addiction and neural disorders. Not to mention cancer and ageing, processes of development, the gut microbiome, stem cells, muscles and the heart.