High School Fruit Fly Lab
Fruit Fly Lab
Alycia Fletcher
Biology IB HL
March 25th 2010
Fruit Fly Lab
Introduction
Genes can either be sex-linked or autosomal. If a gene appears mostly in one sex chances are the gene is sex-linked and if it appears frequently in both sexes it is most likely autosomal. Using Drosophila melanogaster, also known as the fruit fly, we will determine whether the gene is sex-linked or autosomal. Drosophila melanogasters have a relatively short life span and are an excellent organism for genetic studies because it has simple food requirements, occupies little space, is hardy, completes its life cycle in about 12 days at room temperature, produces large numbers of offspring, can be immobilized readily for examination and sorting, and has many types of heredity variations that can be observed with low power magnification. Drosophila has a small number of chromosomes (four pairs). These chromosomes are easily located in the large salivary gland cells.
Purpose
The idea of this experiment is to give a clearer understanding between autosomal, sex-linked, recessive and dominant genes. Furthermore, with this knowledge we can then understand how a gene is passed down through its generations and why it would appear in one individual and not in another. The experiment also helps give a better understanding of genotypes and phenotypes and what role they play in determining and predicting a genotype.
Hypothesis
Null: The wingless mutation is autosomal recessive Alternative: the wingless mutation is sex-linked
The Life Cycle of Drosophila
The eggs: The eggs are small, oval shaped, and have two filaments at one end. They are usually laid on the surface of the culture medium and, with practice, can be seen with the naked eye. The eggs hatch into larvae after about a day.
The larval stage: The worm like larvae eats most continuously, and its black mouth parts can be seen moving back and forth even when the larvae are less distinct.
Alycia Fletcher
Biology IB HL
March 25th 2010
Fruit Fly Lab
Introduction
Genes can either be sex-linked or autosomal. If a gene appears mostly in one sex chances are the gene is sex-linked and if it appears frequently in both sexes it is most likely autosomal. Using Drosophila melanogaster, also known as the fruit fly, we will determine whether the gene is sex-linked or autosomal. Drosophila melanogasters have a relatively short life span and are an excellent organism for genetic studies because it has simple food requirements, occupies little space, is hardy, completes its life cycle in about 12 days at room temperature, produces large numbers of offspring, can be immobilized readily for examination and sorting, and has many types of heredity variations that can be observed with low power magnification. Drosophila has a small number of chromosomes (four pairs). These chromosomes are easily located in the large salivary gland cells.
Purpose
The idea of this experiment is to give a clearer understanding between autosomal, sex-linked, recessive and dominant genes. Furthermore, with this knowledge we can then understand how a gene is passed down through its generations and why it would appear in one individual and not in another. The experiment also helps give a better understanding of genotypes and phenotypes and what role they play in determining and predicting a genotype.
Hypothesis
Null: The wingless mutation is autosomal recessive Alternative: the wingless mutation is sex-linked
The Life Cycle of Drosophila
The eggs: The eggs are small, oval shaped, and have two filaments at one end. They are usually laid on the surface of the culture medium and, with practice, can be seen with the naked eye. The eggs hatch into larvae after about a day.
The larval stage: The worm like larvae eats most continuously, and its black mouth parts can be seen moving back and forth even when the larvae are less distinct.