The fruit fly might seem like a mild annoyance to the everyday person, yet its contribution to science is legendary. For many decades, it has been vital in studying genetics and has provided powerful breakthroughs during the birth of this fascinating and significant field.
The fruit fly, or Drosophila melanogaster, was one of the first organisms used in the study of genetics. The first one to use it is generally recognized as Charles W. Woodworth, and he suggested its use to W.E. Castle. Its use spread dramatically.
In 1910, Thomas Hunt Morgan used fruit flies while performing experiments in heredity. At Columbia University, he created “The Fly Room,” located in Schermerhorn Hall. With the Drosophila melanogaster as his powerful tool, he studied all different aspects of genetics. From this small cramped room emerged some of the first discoveries in genetics such as sex-linked inheritance, epistasis, multiple alleles, and gene mapping. They were able to show that independent assortment is not on genes of the same chromosome. They confirmed the genes’ location on chromosomes, and maps with the location of genetic loci on chromosomes were produced. Alfred Sturtevant completed maps on the chromosomes of the fruit flies.
Fruit flies allowed scientists to first see the genetic variations present in both individuals and species. Theodosius Dobzhansky was a Russian biologist who gave much to the field of genetics with the help of Drosophila melanogaster. He showed that flies from different areas had different bending patterns on their chromosomes, proving that the population was not uniform among different locations. He also showed that these variations could change over time, even at different times of the year. This truly was revolutionary information at the time. It showed that evolution could occur in rapid succession. It gave important substance to the theories of evolution and the origin of species and provided an excellent way to experiment and provide scientific empirical results.
Dobzhansky also showed how populations can produce ever-changing differences such as in size, color and other characteristics. As these differences grew, the different subsets would at times halt mating with each other, bringing out new species. Never before had this birth of a species been so scientifically described. His work was groundbreaking, and the fruit flies played a large part in it.
It is no coincidence that Drosophila melanogaster has played such an important role in genetics. They are abound in traits that make them suitable subjects. First, they are easy to care for and grow, and require little equipment or space because of their small size. They are inexpensive. Once they are anesthetized, their morthology is easily identified. Their large and undivided chromosomes are easily studied, and when stained, they show dark bands that indicate the locations of genes.
The generation time of the Drosophila melanogaster is only about ten days, thus multiple generations can be examined in a short period of time, providing a lot of information for studies. Females lay 2000 eggs in their lives (up to a hundred a day) giving large amounts. It is easy to tell the difference between the genders. Four pairs of chromosomes make it easier to study them. Giant chromosomes are shown in the salivary glands (polytine chromosomes) showing activities of genes. Additional factors make them a suitable study subject, allowing for many genetic discoveries.
Another advantage is that three quarters of identified human diseases are seen in fruit flies. These might therefore aid in the study of a variety of significant human conditions, including Parkinson’s Disease, Alzheimer’s Disease, diabetes, cancer and even drug use.
Drosophila melanogaster not only started a revolution in genetics, but continues to be studied extensively today. All of the attributes that made it such as useful and sensible study subject still hold true today. The discoveries from it have a wide range of positive results in applied and clinical genetics.
Resources:
http://www.guardian.co.uk/science/2001/mar/29/technology2
http://en.wikipedia.org/wiki/Drosophila_melanogaster
