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Chapter 9:1-10 Inheritance - Mendelian Simple Traits

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Biology Homework Chapter 9: Mendelian Inheritance


Reading Preparation

Textbook assignment: Chapter 9: Patterns of Inheritance, sections 1-10

Study Notes

Web Lecture

Read the following weblecture before chat: Mendelian Inheritance

Take notes on any questions you have, and be prepared to discuss the lecture in chat.

Study Activity

Perform the study activity below:

Use the Classical Genetics simulator to explore traits in Drosophila populations. Clcik on "Learn more" to read the instructions. You do not need to log into an account to use this exercise; we will use the practice populations only. You will not be able to save your population, but the exercise should give you a sense for how inheritance can be determined.

Chose "Select a Practice Population" and when you see the first practice population, note the purpose (segregating body time for autosomal inheritance) into dominant wild type and recessive tetrapter types. Click on "Continue".

  • In the lab, click on the Stats tab and note the number of body types present. Estimate the best whole-number expected ratios for your sample. For example, if you have a random population with a single simple trait, 75% should show the dominant trait and 25% should show the recessive trait. Enter these values and calculate the Chi-Square value for your data.
  • Click on the organism tab and sort by body types and display body types. Are all specimens showing the recessive trait homozygous? Are all specimens showing the dominant body type homozygous?
  • Predict the relative ratios of body types in new populations if you breed
    • Recessive to recessive
    • Recessive to true-breeding dominants
    • Recessive to heterozygous dominants
  • Sort by sex but display body types. Then perform the crosses for which you made predictions (these will inhabit new vials). Select each vial and view the stats on it; enter your prediction and compare the Chi-square value with the actual results.

Chat Preparation Activities

Chapter Quiz

Lab Work

Read through the lab for this week; bring questions to chat on any aspect of the lab, whether you intend not perform it or not. If you decide to perform the lab, be sure to submit your report by the posted due date.