Inheritance: It Runs In the Family

Introduction

You are going to use an online learning object to explore the heritable characteristics of fruit flies. A heritable characteristic is one that is passed on from generation to generation. Fruit flies have heritable characteristics such as straight wing/curled wing and red eyes/brown eyes that can be easily identified. You will complete a simulation that will have you examine several combinations of heritable characteristics to determine whether they are dominant or recessive traits.

Problem


Procedure

Test I Pure Red Eyed X Pure Brown Eyed

1. / Click on the diagram above to launch the learning object.
2. / Mouse over the fruit fly (DMG) on the top shelf and follow his instructions. You will be repeating the steps of his instructions several times, so try to remember them.
3. / Place a pure red eyed female and a pure brown eyed male in the breeding vial.
4. / Record your prediction for pure red eyed and pure brown eyed parents in the Data Table provided.
5. / Follow DMG's instructions and observe the offspring with the binocular microscope. Separate the offspring into red eyed and brown eyed groups.
6. / Record your observed count for pure red eyed/pure brown eyed offspring in the data table.

Test 2 Hybrid Red Eyed X Hybrid Red Eyed

1. / Place a hybrid red eyed female and a hybrid red eyed male in the breeding vial.
2. / Record your prediction for hybrid red eyed parents in the Data Table provided.
3. / Follow DMG's instructions and observe the offspring with the binocular microscope. Separate the offspring into red eyed and brown eyed groups.
4. / Record your observed count for pure red eyed/pure brown eyed offspring in the data table.

Test 3 Pure Straight Wing X Pure Curled Wing

1. / Place a pure straight wing female and a pure curled wing male in the breeding vial.
2. / Record your prediction for pure straight wing and pure curled wing parents in the Data Table provided.
3. / Follow DMG's instructions and observe the offspring with the binocular microscope. Separate the offspring into straight wing and curled wing groups.
4. / Record your observed count for pure straight and pure curled wing offspring in the data table.


Test 4 Hybrid Straight Wing X Hybrid Curled Wing

1. / Place a hybrid straight wing female and a hybrid straight wing male in the breeding vial.
2. / Record your prediction for hybrid straight wing parents in the Data Table provided.
3. / Follow DMG's instructions and observe the offspring with the binocular microscope. Separate the offspring into straight wing and curled wing groups.
4. / Record your observed count for hybrid straight wing offspring in the data table.
5. / Complete the inference section at the bottom of the data table.

Observations

Test / Parent 1 / Parent 2 / Predicted Count (out of 8) / Observed Count (out of 8)
1 / pure red eyed / pure brown eyed / red eyed / red eyed
brown eyed / brown eyed
2 / hybrid red eyed / hybrid red eyed / red eyed / red eyed
brown eyed / brown eyed
3 / pure straight wing / pure curled wing / straight / straight
curled / curled
4 / hybrid straight wing / hybrid straight wing / straight / straight
curled / curled

Analysis

1. / What heritable traits of fruit flies are dominant?
2. / What parent combination would produce offspring that all have brown eyes?
3. / Big DMG has brown eyes and curled wings but his parents and siblings have red eyes and straight wings. Is this possible? What trait combination of traits in his parents would produce this result?

Extension

You have done four simulations with two heritable traits of fruit flies. You can now see that the ratio of offspring that result from different combinations of these traits is predictable. What parent combination might result in an equal number of offspring having straight and curled wings? Use the Explore mode of the learning object to set up and test your prediction.

Credits

The learning object was developed by LearnAlberta and can be found in the Cyber-Science section for Grade 9.

Inheritance: It Runs In the Family 3