Download Human Genome Race

VGEC: Teacher Notes
Human Genome Race
A fun activity in which children – working as individuals or in groups – race to join together a number of
overlapping DNA sequences to form a full sequence. The activity can be used to illustrate aspects of
genome sequencing or as an ice-breaker before discussions on the ethical implications of the Human
Genome Project.
The activity works well when done as a competition between small groups: Which group will be the first to
assemble the ‘human genome’ (as a paper sequence)?
At the end, the students can see how a computer can assemble the same sequence in a fraction of a
second.
The activity can be used to introduce and illustrate the process of DNA sequencing. The game mirrors the
final stage of the sequencing process, in which the complete sequence is constructed by linking together the
sequences of smaller, overlapping, fragments. It is, of course, a very simple simulation of the final stage of a
much more complicated procedure.
The race can be done in two formats: a short version using 20 DNA fragments or a longer, more difficult,
version using 26 DNA fragments.
Intended learning outcomes

To understand that DNA sequencing involves identifying the sequence of the four nucleotide bases in a
DNA molecule: adenine (A), thymine (T), cytosine (C) and guanine (G).

To recognise that the process of sequencing involves a number of steps:
– breaking DNA molecules into a number of smaller, overlapping fragments
– identifying the sequence of these fragments
– joining these smaller sequences together to produce the sequence of a complete molecule.
Possible curriculum links
Key Stage 3: 1.2
Applications and implications of science
Files provided
1 GenomeRace.docx/rtf/pdf
This document – includes Teacher Notes.
2 GenomeRaceStrips.docx/rtf/pdf
A document containing the DNA sequences used in the activity.
3 HumanGenomeProject.pptx/pdf
A two-slide PowerPoint presentation that illustrates the activity, and
shows how quickly a computer can match the fictional sequences [optional].
4 GenomeRacePoster.pptx/pdf
A poster to accompany the activity [optional].
Virtual Genetics Education Centre: http://www.le.ac.uk/ge/genie/vgec/
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Key vocabulary

DNA (short for deoxyribonucleic acid): DNA is the chemical that genes are made from.

Nucleotide base: One of four chemicals – adenine (A), thymine (T), cytosine (C) and guanine (G) –
that form the ‘letters’ of the DNA code.

DNA sequencing: the process of identifying the sequence of nucleotide bases in a given DNA
molecule.
Main points

DNA molecules are long chains made of four nucleotide bases – adenine (A), thymine (T), cytosine (C)
and guanine (G).

To sequence DNA scientists must identify the exact order of the bases in a molecule. This process
involves a number of steps:
– the DNA is cut into a number of small, overlapping, pieces of different lengths
– the order of the bases in the small pieces of DNA is identified by an automatic sequencing machine
– the computer links together the sequences of the smaller pieces of DNA to produce the complete
sequence.

This activity mirrors the final step in the process: the construction of the complete sequence from a
number of smaller sequences. In reality, the process is much more complicated, however. First, a
collection of DNA molecules is split into fragments about 500 base pairs long (longer than the fragments
used here). These fragments are sequenced, and a lot computing power is required to construct the full
sequence. The size of the fragments, and the size of the overlaps at the ends of the fragments, varies a
great deal.

The real DNA molecules are double stranded and both – complementary – strands are sequenced. In
this activity only one strand is shown.
Background facts

By April 2003, scientists working on the Human Genome Project had succeeded in identifying the
sequence of bases – A, T, C and G – in the complete human genome.

The human genome is the complete list of coded instructions needed to make a person. It consists of 3
billion ‘letters’ (base pairs). If all 3 billion letters were spread out 3 mm apart, they would be 9000 km
long – the distance from Leicester to San Francisco!

A sequencing machine can only read short DNA pieces. The whole genome sequence has to be cut
into small pieces in order to be deciphered.

The small sequence pieces have to be put back together by a computer. The computer looks for
overlapping sequences. Only the computer can do such a complex job, and even then the human
genome took powerful computers years to compile.

The deciphering of the human genome was a ‘race’ between a publicly funded international consortium
and the firm Celera. Both published a draft version of the human genome on 26 June 2000.

The sequence of the human DNA is stored in databases available to anyone on the Internet.
Procedure

Print out, cut out and laminate the sequences in the file GenomeRaceStrips.pdf

For the short version of the activity, use the first 20 DNA fragments (pages 1 to 3). This takes from 3 to
5 minutes.

For the longer version of the activity, use the full 26 DNA fragments (pages 1 to 4). This takes
approximately one minute longer than the 20-fragment version.
Virtual Genetics Education Centre: http://www.le.ac.uk/ge/genie/vgec/
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
Mix the fragments – face down – and time the students as they reconstruct the full sequence by linking
the fragments together. Alternatively, the activity can be organised as a direct race: the first team to
produce the full sequence is the winner.
Virtual Genetics Education Centre: http://www.le.ac.uk/ge/genie/vgec/
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