GB2287571A - DNA fingerprinting educational game - Google Patents

Abstract

An educational game for teaching DNA fingerprinting comprising a plurality of groups of rectangular strips 10 each group being associated with a corresponding one of a plurality of students and each group comprising a plurality of pairs of said strips 10, the strips 10 of each pair being of equal dimension one to another and of different dimension to other pairs in the same group and some of the strips 10 in each group carrying indicia 12 which are applied to the strips 10 at random except that a combination in one group is replicated to form a master array. When the strips of each group are arranged by the corresponding student in a sequence corresponding to the sequence of the strips comprising the master array thereby to form a student array of strips, a culprit student is identified by a student array which corresponds to the master array. <IMAGE>

Description

An Educational Game This invention relates to an educational game and, more particularly, to an educational game for demonstrating forensic investigation using samples of Deoxyribonucleic Acid (DNA) taken from living organisms, such being generally referred to as DNA fingerprinting.

According to the present invention, there is provided an educational game for teaching DNA fingerprinting comprising a plurality of groups of rectangular strips each group being associated with a corresponding one of a plurality of students and each group comprising a plurality of pairs of said strips, the strips of each pair being of equal dimension one to another and of different dimension to other pairs in the same group and some of the strips in each group carrying indicia which are applied to the strips at random except that a combination in one group is replicated to form a master array the arrangement being such that, when the strips of each group are arranged by the corresponding student in a sequence corresponding to the sequence of the strips comprising the master array thereby to form a student array of strips, a culprit student is identified by a student array which corresponds to the master array.

The game is intended to provide an enjoyable and interesting method of instructing students in the steps involved in DNA fingerprinting, these are: Step 1: Obtaining the DNA A target sample of DNA is obtained from organic matter, such as blood, believed to have issued from the body of a suspected culprit of an offence and futher samples of DNA are obtained from donors. Since DNA sequences are unique for each human being, as with human fingerprints, correspondence of a donor sample with the target sample is proof that the two samples have issued from the same body.

Step 2: Digesting the DNA with restriction enzynmes The samples of DNA are subjected to the action of restriction enzymes which have the effect of digesting the DNA and generating a number of different sized fragments.

Step 3: Electrophoreses The fragments of each sample are separated on agarose gels.

Their movement through the gel is inversely proportional to the size of the DNA. The smaller the fragment the faster and consequently further it moves through the gel.

Step 4: Southern blot the gel The separated DNA is transferred from the gel to a nitrocellulose or nylon membrane by capillary action. Before transfer the DNA is first denatured by soaking in alkali.

Step 5: Hybridisation The membrane is then swept by a DNA probe carrying a strand of the target DNA duplex. If the sample DNA on the membrane is from the same source as the target DNA, a strand on the membrane will bind to the probe. This is proof that the sample DNA and the target DNA are from the same source because only one strand of the original DNA duplex will be able to bind with the probe as only one strand will be complementary.

Step 6: Autoradiography The probe is radioactive and is placed adjacent an X-ray film so that a radioactive pattern corresponding to the pattern on the membrane is recorded on film. The film is placed over a filter to detect the pattern to establish corelation.

In playing the game in accordance with the present invention, the above six steps are simulated.

The game comprises a plurality of boards, each intended for use by a corresponding one of a plurality of students and each of the boards having an upper surface coated with a release substance, such as silicone; a plurality of elongate rectangular strips of paper each of approximately 36" x 0.5", each having a central longitudinal line printed thereon and each having on a reverse surface thereof a peelable pressure sensitive adhesive; a vessel containing a concentrated solution of sodium molybdate; a vessel containing a concentrated solution of gallic acid; a paint brush; a marker pen; and a pair of scissors.

Following is a description, with reference to the accompanying drawings, as to how the game is played.

In the drawings: Figure 1 is a plan view of a rectangular strip of the game which has been folded along the central longitudinal line thereof and which has been provided with spaced transverse lines between selected pairs of which is painted a coating of sodium molybdate, thereby simulating step 1 referred to above, Figure 2 is a plan view of the strip after having been cut along the transverse lines and cut fragments having been arranged in an array of rows of decreasing length, thereby simulating step 3 referred to above, Figure 3 is a plan view of a double array formed by cutting each strip along a longitudinal line thereof and providing a second array from the previously folded under portions of the strips, the strips of both arrays being applied by adhesive thereof to the upper surface of a board, thereby simulating step 4 referred to above, Figure 4 is a plan view of the double array shown in Figure 3 after the strips have been painted with gallic acid, thereby simulating step 5 referred to above and, Figure 5 is a plan view of the double array in which the strips of one array are superimposed on corresponding strips of the other array, thereby simulating step 6 referred to above.

Referring now to the drawings, the game is played by each student taking a corresponding one of the strips 10 and folding it along the central printed line thereof so that the adhesive coatings thereof temporarily unite one with another.

The student then marks with the marker pen one surface of the strip with transverse spaced parallel lines 11 at random spacing, as shown in Figure 1. With the paintbrush, the student then paints between selected pairs of lines 11, say between two to five pairs, a coating of the molybdate paint, which is colourless, to form rectangular bars 12. The student then uses the scissors to cut the strip along the transverse lines 11 to form a group of longitudinally folded filaments.

Meanwhile, a teacher carries out the same process with two such strips ensuring that at the end of the process there are two identical groups. The teacher collects the groups from all of the students, withdraws one of the groups and substitutes one of the pair of groups that the teacher has prepared. The other group of the pair is retained by the teacher. The teacher then returns the groups to the students at random so that each student has one group.

Each student then lays out the filaments of the corresponding group received by the teacher in rows of progressively smaller length so that the largest is in an upper row and the smallest is a lower row, as shown in Figure 2, filaments of identical size being placed one beside the other.

The student then cuts each filament along the longitudinal line thereof and adhesively applies the filaments on an upper surface of a corresponding board (not shown) so that the filaments are arranged in two identical arrays one beside the other on the board, as shown in Figure 3.

The student then paints all of the filaments of both arrays with a coating of the gallic acid, which is colourless. The filaments which have previously been coated with sodium molybdate change colour to brown due to the reaction of the gallic acid with the sodium molybdate, as shown in Figure 4.

The student then peels the filaments of one of the two arrays from the board and replaces them on the corresponding filaments of identical size in the other array still attached to the board, ensuring that any brown coloured filaments comprise an upper layer, as shown in Figure 5.

The student then places a sheet of translucent paper over the combined arrays and traces on the sheet an outline of the pattern formed by the brown coloured areas, thereby creating on the sheet a student array. The array should be unique for each student. The student array created by one of the students, a "culprit" array, will have been formed from one of the duplicate groups of strips 10 provided by the teacher. Meanwhile, the teacher will have carried out the same procedure with the other of the duplicate group of strips 10 to provde a "master" array.

By comparing each student array with the master array, the student who created the culprit array can be identified.

Claims (5)

Claims

1. An educational game for teaching DNA fingerprinting comprising a plurality of groups of rectangular strips each group being associated with a corresponding one of a plurality of students and each group comprising a plurality of pairs of said strips, the strips of each pair being of equal dimension one to another and of different dimension to other pairs in the same group and some of the strips in each group carrying indicia which are applied to the strips at random except that a combination in one group is replicated to form a master array the arrangement being such that, when the strips of each group are arranged by the corresponding student in a sequence corresponding to the sequence of the strips comprising the master array thereby to form a student array of strips, a culprit student is identified by a student array which corresponds to the master array.

2. A game as claimed in Claim 1 wherein the indicia comprise a coating of a first colourless substance which becomes coloured when reacted with a second colourless substance.

3. A game as claimed in Claim 2 wherein the first substance is sodium molybdate and the second substance is gallic acid.

4. A game as claimed in any one of the preceding Claims wherein each of the strips is coated on a reverse surface thereof with a pressure sensitive peelable adhesive.

5. An educational game substantially as hereinbefore described and as illustrated in the accompanying drawings.