Gene genius in a bottle

7th February 2003 at 00:00
A new kit allows even young pupils to collect samples of their own DNA. Bernard Adams reports

While many people may not know what DNA stands for - deoxyribonucleic acid - most will know what it is. It is our genetic fingerprint, the sequence of chemicals that makes us what we are.

Manipulating it could extend our lives, decoding it helps catch criminals.

It is the stuff that will reveal whether the Raelian cult is telling the truth about having cloned a human.

As we learn more about DNA, its mystique is being stripped away - and not just in the academic and corporate research laboratories. It is now possible to carry out DNA extraction in a modest school lab. The procedure is made possible through a Genes in a Bottle kit provided by the education arm of Bio-Rad laboratories. The kit consists of the necessary chemicals, a variety of test tubes, disposable plastic pipets, cytology brushes (for the collection procedure) and guides for teachers and students. Shirley Dabek, head of biology at Ashley Cooper, a comprehensive in Hemel Hempstead, Hertfordshire, says the kit "fits perfectly into our teaching programme for the structure of DNA and Edexcel's Unit 1 on molecules and cells. This kit makes DNA real for the students".

A white-coated A-level class gingerly follows the photocopied instructions:

"Gently scrape the cells from the inside of your right cheek, and from the space between your cheek and gum, with a brush, for one minute; try to collect as much cell material as possible." This is the easy part.

For the extraction procedure itself, the class is led by Leighton Dann, a development teacher from Science and Plants for Schools, based in Cambridge. The students are attentive and concerned about getting the stage-by-stage procedure right. When they have got enough cells onto their brushes and into the tiny capped test tubes, they mix them with a lysis buffer which helps break up the cell membranes.

Next they add a drop of a protease solution, shake the mixture five times and put the tubes in water at 50C for 10 minutes while the unwanted cellular proteins are digested.

From the sidelines, Shirley Dabek poses questions for her students. How much of their mother's and how much of their father's DNA will each student's sample contain? They are so busy with the procedures they take a little while to decide it's 5050.

The next stage is to add two drops of a salt solution to the mixture to help isolate the DNA. There's a bit more shaking and checking before the blend is poured into a test tube. Then ice-cold alcohol is gently added.

The alcohol settles on top, and at the junction with the solution below bubbles begin to form.

"Look, you can see it," says one student as the threads of cotton wool-like DNA attached to the bubbles become visible. These pale biological identity cards are then carefully transferred to a locket, probably the trickiest part of the procedure. Almost two hours after they started, each student proudly displays a sample of his or her own DNA in a necklace locket.

Dr Dominic Delaney of Bio-Rad has been involved in the development of the kit and has found it fulfils a need in schools.

"Until this kit was developed it wasn't possible for students to extract their own DNA. But this is so straightforward it can work in a primary school," he says.

The procedure itself also has value. "It is relevant in terms of the technical manipulation you would do in a research laboratory. This is one of the fundamental techniques of molecular biology."

One of the Ashley Cooper students, Nicola Simson, who had a Nuffield Science bursary last year, says: "I found the whole process was interesting and completely new."

Shirley Dabek is pleased that the kit allows real research techniques to be brought into the classroom. At pound;50 for a class of 36, she thinks the price is reasonable and teachers will probably find the extra cost of the necklaces (another pound;25) worthwhile as they provide a permanent reminder of the experiment.

Genes in a Bottle is available from Bio-Rad Laboratories, Bio-Rad House, Maylands Avenue, Hemel Hempstead HP2 7TD Tel: 020 8328 2000 Fax: 020 328 2550Email: uk.lsg.marketing@bio-rad.comwww.bio-rad.com

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