Genetics & Drosophila Melanogaster Lab Report

Background: For the past two months, you have been breeding Drosphila melanogaster (fruit flies) and setting up genetic crosses in order to apply basic genetic principles. The trait for which we have examined the pattern of inheritance is white eyes. The white eyes fruit flies are mutant strains, and the normal condition red eyed is referred to as the wild type strain.

Objective: The intial cross mated mutant fruit flies with wild type fruit flies in order to produce an F1 generation of offspring. The F1 offspring were mated with each other in order to produce an F2 generation. This results in sufficient data to determine which trait is dominant or recessive, and if the pattern of inheritance is autosomal or sex-linked.

Assignment: You will complete a lab report that includes a title, introduction experimental design, procedure, results, and conclusion. The sections must include the following information.

Introduction:

Part I: Background information about Drosophila melanogaster

Information about the structure of Drosophila melanogaster.

Information about the life cycle of Drosophila melanogaster.

Information about sex markers and sex characteristics of Drosophila melanogaster.

Diagrams of male and female mutant flies. (may include diagrams in experimental design)

Diagrams of male and female wild type flies.

Part II: Genetic applications

Statement of purpose: in order to determine patterns of inheritance for the mutant apterous (wingless) strain in fruit flies

Hypothesis: Predict the % of offspring that will exhibit the dominant and recessive trait in both the F1 generation and F2 generation, based on whether the trait is autosomal or sex-linked.

Experimental Design:

Show phenotypes and genotypes of P1 cross, and then the F1 cross.

You may include diagrams of fruit flies as part of your experimental design

List constant conditions for this experiment

Procedure:

List the steps necessary to set up each cross.

List the method used to count and record characteristics of fruit flies.

Important: Tell the dates when each of these steps was completed.

Results:

Create data tables of the numbers of resulting offspring that exhibit the dominant and recessive trait from each cross.

Calculate the following percentages…

F1 offspring

% mutant % wild type (of only males)

% mutant & % wild type (of only females)

% mutant & % wild type (of all flies)

F2 offspring

% mutant & % wild type (of only males)

% mutant & % wild type (of only females)

% mutant & % wild type (of all flies)

Conclusion:

Tell which trait is dominant and which trait is recessive or if the pattern shows incomplete dominance.

Tell if the trait is sex-linked or autosomal.

Site your data to explain your reasoning.

Show Punnett squares for the P1 and F1 crosses.

Compare the actual percentage (from the crosses) to that of the predicted percentages as derived from the Punnett Square.

Complete a chi squared valued

Offer suggestions and recommendations for future study.