VGEC: Activity Notes
RESTRICTION ENZYME MAPPING OF
THE λ (lambda) PHAGE GENOME
This is a paper exercise where students use gel images of restriction enzyme digest data
to construct a physical map of the phage lambda genome. It shows how restriction
endonucleases are used as tools for the molecular analysis of complex genomes such as
those of mammals.
As this exercise is part of the Genomes module which is currently taught to
undergraduate students, the final answer is not provided online. If you are going to run
this tutorial for your class and need the answers, then please click the link below,
complete the online form, and we will email them to you separately.
Answers
Intended learning outcomes

To familiarise students with one of the many molecular techniques that can be
used to address problems relating to genome research and genetics.

To understand more about gel electrophoresis and how the results can be
analysed and used

To be able to construct a physical map of a genome from restriction digest data

To think about alternative techniques which can be used where the digest data is
not able to answer unresolved fragment locations
Files provided
1. Fragment Activity.docx/rtf/pdf
This document, which sets out the aims of the
activity.
2. StudentNotes.docx/rtf/pdf
Student Notes, containing instructions for the
student.
3. Semilog100.pdf
3-cycle semilog graph paper (needed for fragment size
calculations).
Virtual Genetics Education Centre: http://www.le.ac.uk/ge/genie/vgec/index.html
4. FragmentSizes.pdf
A sheet containing the correct fragment sizes to be given to
students after they have attempted to work these out for
themselves first.
5. LambdaComplete.pdf Gel pictures of the complete digests.
6. LambdaPartial.pdf
Gel pictures of partial and deletion mutant digests
Procedure
Students should work in pairs, or on their own to do this exercise.
They are provided with the Student Notes, the Semilog graph paper, and the gel pictures
of the complete and partial and deletion mutant digests.
The students need to calculate the fragments sizes, and once they have these, they are
then provided with the Fragment sizes document which they use to work out the actual
map of the λ phage genome.
The students then need to think about alternative methods for resolving the positions of
the last fragment sizes.
Materials
Graph paper (provided)
Plain paper
Rulers
Pens
Pencils
Virtual Genetics Education Centre: http://www.le.ac.uk/ge/genie/vgec/index.html