The very small fly, Drosophilidae, which is commonly used as a laboratory insect and is often is found indoors, is one. The larger, outdoor fly that causes problems for fruit growers, Tephritidae, which causes problems particularly for blueberries, cherries, and apples, is the other.
A quick and simple introduction to Drosophila melanogaster What is it and why bother about it? Drosophila melanogaster is a fruit fly, a little insect about 3mm long, of the kind that accumulates around spoiled fruit. It is also one of the most valuable of organisms in biological research, particularly in genetics and developmental biology.
Drosophila has been used as a model organism for research for almost a century, and today, several thousand scientists are working on many different aspects of the fruit fly.
Why work with Drosophila? Part of the reason people work on it is historical - so much is already known about it that it is easy to handle and well-understood - and part of it is practical: Mutant flies, with defects in any of several thousand genes are available, and the entire genome has recently been sequenced.
Life cycle of Drosophila The drosophila egg is about half a millimeter long. It takes about one day after fertilisation for the embryo to develop and hatch into a worm-like larva. The larva eats and grows continuously, moulting one day, two days, and four days after hatching first, second and third instars.
After two days as a third instar larva, it moults one more time to form an immobile pupa. Over the next four days, the body is completely remodelled to give the adult winged form, which then hatches from the pupal case and is fertile within about 12 hours.
Research on Drosophila Drosophila is so popular, it would be almost impossible to list the number of things that are being done with it. Originally, it was mostly used in genetics, for instance to discover that genes were related to proteins and to study the rules of genetic inheritance.
More recently, it is used mostly in developmental biology, looking to see how a complex organism arises from a relatively simple fertilised egg. Embryonic development is where most of the attention is concentrated, but there is also a great deal of interest in how various adult structures develop in the pupa, mostly focused on the development of the compound eye, but also on the wings, legs and other organs.
The Drosophila genome Drosophila has four pairs of chromosomes: The fourth chromosome is quite tiny and rarely heard from. The size of the genome is about million bases and contains and estimated 14, genes by comparison, the human genome has 3, million bases and may have about 22, genes; yeast has about genes in The genome was almost completely sequenced inand analysis of the data is now mostly complete.
Several other insect genomes have now been sequenced, including many Drosophila species, and the genomes of mosquito and honey bee, and these are starting to show what is common among all insects, and what distinbuishes them from each other.
Polytene Chromosomes These are the magic markers that first put Drosophila in the spotlight. As the fly larva grows, it keeps the same number of cells, but needs to make much more gene product. The result is that the cells get much bigger and each chromosome divides hundreds of times, but all the strands stay attached to each other.
The result is a massively thick polytene chromosome, which can easily be seen under the microscope. Even better, these chromosomes have a pattern of dark and light bands, like a bar code, which is unique for each section of the chromosome.
As a result, by reading the polytene bands, you can see what part of the chromosome you are looking at. Any large deletions, or other rearrangements of part of a chromosome can be identified, and using modern nucleic acid probes, individual cloned genes can be placed on the polytene map.
The standard map of the polytene chromosome divides the genome into numbered bands is the X, is the second, the third and the fourth ; each of those is divided into six letter bands A-F and those are subdivided into up to 13 numbered divisions the picture above shows band The location of many genes is known to the resolution of a letter band, usually with a guess to the number location e.
The polytene divisions don't have exactly the same length of sequence in them, but on average, a letter band contains about kb of DNA and genes.
Finding out more Many biology and develomental biology textbooks have chapters on Drosophila. There are fewer books devoted specifically to Drosohphila; here are some links are to the Amazon.
Probably the easiest simple introduction to Drosophila development and quite readable. Probably out of print, but should be in many academic libraries. The Development of Drosophila melanogaster ed.
The enclosed picture "Atlas of Drosophila development" is a very useful tool and is available separately. Biology of Drosophila ed.
Demerec; Cold Spring Harbor Press, A dense, sometimes hard-to-read but detailed and exhaustive account of embryonic development, the 'green book' as it is called is a standard reference. Here's a review page from the second edition. Techniques Drosophila, a Practical Approach ed.Fruit Fly Lab Introduction The major topic of this experiment was to examine two different crosses between Drosophila fruit flies and to determine how many flies of each phenotype were produced.
Phenotype refers to an individual's appearance, where as genotype refers to an individual's genes.
Introduction to Fruit Flies Fruit flies or fruitflies are names used for two different species of flies. The very small fly, Drosophilidae, which is commonly used as a laboratory insect and .
The Lives of a Fly by Mary Tyler is a VHS video which gives a general introduction to fly development. Drosophila images (through FlyBase). Animations of Embryogenesis, by morphing of SEM images, by Thom Kauffman & Rudi Turner. An Introduction to Drosophila melanogaster. Drosophila melanogaster is a small, common fly found near unripe and rotted fruit.
It has been in use for over a century to study genetics and behavior. Thomas Hunt Morgan was the preeminent biologist studying Drosophila early in the ’s.
Drosophila melanogaster is a fruit fly, a little insect about 3mm long, of the kind that accumulates around spoiled fruit. It is also one of the most valuable of organisms in biological research, particularly in genetics and developmental biology.
The Fruit Fly Optimization Algorithm is an easy evolution algorithm for maximizing global optimization based on the food searching behavior of the fruit fly swarm.
Fruit flies have better senses and perceptions than other species, particularly its olfactory and visual senses.