Working with Drosophila BTEC Applied Science Unit 18: Genetics Assignment 3: Inheritance

Starter Quiz For Each question, write down the answer in your notes…

Question 1: Which is the Male fly? B A

Question 2 What mutation is this fly displaying?

Question 3 Which Mutation is this fly displaying?

Question 4: What would be the ‘phenotype’ of a fly with the following genotype: vg+vg+ebeb

Question 5 What would be the ‘phenotype’ of a fly with the following genotype: vgvg eb+eb+

Question 6 Is this fly male or female?

Answers: B Vestigial Wings Ebony body Ebony body, non vestigial wings Vestigial wings, non-ebony body Male

Lesson Objectives: 1. To know how to handle, anaesthetise and sex drosophila melanogaster (fruit flies) 2. To understand how/why X-Linked inheritance can produce unexpected outcomes in the offspring.

Drosophila Use the Fly Nap to put the flies to sleep (follow instructions given in class) Empty some flies onto a petri dish. Use a paintbrush to move them around if needed. Observe the flies using a hand lens or microscope. Keep a record of the number of male and female flies and note down what their phenotypes are.

X – Linked Inheritance Some alleles are carried on the X-Chromosome. (what do you know about the X chromosome?) We refer to this type of inheritance as ‘X-Linked Inheritance’ or ‘Sex-Linked Inheritance’