Formal Lab Genetics

Formal Lab Genetics

  • Submitted By: swimmer911
  • Date Submitted: 02/04/2014 11:27 AM
  • Category: Science
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Determining two unknown mutations present in Drosophila melanogaster by designing and conducting crosses using FlyLab.

By X
Bio 2133 Section A6


March 21st, 2013

Department of Biology


When one is given two unknown mutations, how does one discover what type of mutations they are? What experiments can be conducted to prove whether the mutations are dominant or recessive, sex-linked or autosomal, lethal or not, hypostatic or epistatic? Using FlyLab, six different crosses were designed, tested and analyzed to see what phenotypic ratios were given and what type of mutation curly wings and sepia eyes are. During the lab, the F2 generation of the curly winged mutation resulted in a 2:1 ratio, leading to the assumption that the curly winged mutation is a lethal mutation. The F2 generation of the sepia-eyed mutation, however, resulted in a 3:1 ratio, where the wild type phenotype dominated over the sepia-eyed phenotype. This lead to the conclusion that sepia eyes is a recessive autosomal mutation. When both mutations were crossed with each other, there was no interaction between the genes. This allows us to conclude that no epistasis occurs between the two mutations when they are crossed with one another. During this lab, these conclusions will be analyzed and their significance will be discussed.


There are two different mutations that are to be analyzed in this lab. What are the two different types of mutation? Are they autosomal recessive, autosomal dominant, sex-linked recessive, sex-linked dominant or lethal? Does epistasis occur between the two mutations? If so, which mutation is epistatic and which is hypostatic? Using FlyLab, Monohybrid and Dihybrid crosses will be conducted to test which type of mutation the unknown mutations are. The following definitions are according to Klug et al. A Monohybrid cross is a genetic cross involving only one character and a Dihybrid cross is a genetic cross...

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