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Can a zebrafish change its spots?

When should we start talking to children about the use of animals in research? At the recent Edinburgh International Science Festival, MRC Regional Communications Manager Hazel Lambert added an encounter with two tanks of zebrafish into the Mini Scientists activity. The result? Lots of questions about spots and stripes.

Never underestimate your audience. Especially not when they are seven years old, dressed in a lab coat, with a pen poised over a clip board and ready to make a virus, remodel a city and extract some slimy-looking DNA from even slimier pea-juice.

The MRC’s Mini Scientists activity at the Edinburgh International Science Festival is usually booked out and feedback tells us that the kids, their parents and our dedicated volunteers all love taking part. But, after having run the activity for three years, I felt I wasn’t telling the audience the whole story.

A lot of medical research relies on flies, fish, frogs and mice. Most research institutes I know are linked to an animal house, but these research participants were invisible to our Mini Scientists. So this year I brought some in. With the help of the fish team at the MRC Human Genetics Unit (MRC HGU), Mini Scientists were joined by two tanks of zebrafish, a tiny tropical fish the MRC HGU uses in skin cancer research.

All the fish were ‘wildtype’, meaning they’re like the zebrafish found in the wild, rather than those genetically modified for research. The first shoal had spots and naturally ragged fins, while the second flicked and flashed their neat blue stripes. The MRC team used this spots-or-stripes difference between the shoals to start conversations about DNA, genetic variation, and how and why the fish are used in medical research. The kids looked at the fish during the three-minute break in the DNA extraction activity; never confuse pea juice with pee juice or at least one Mini Scientist will get the giggles.

The zebrafish in one tank were spotty, while in the other they were striped

The zebrafish in one tank were spotty, while in the other they were striped

We told the kids that zebrafish are used as models for humans, even though we don’t look much like each other. It only took a few moments of gazing into the tanks for the kids to start listing similarities between the fish and themselves, often accompanied by rolling ‘fish’ eyes and pouting ‘fish’ mouths. Then the questions started trickling out.

Can the fish see us through the glass? Are spotty fish more likely get to skin cancer because they already have round spots? Can I feed them? Do fish have ears? What can you actually learn from a fish that has anything to do with people? How do the fish get cancer? Have you ever seen a piranha?

The team used the kids’ questions as starting points to get to the message that by studying the fish, scientists can look for ways to treat skin cancer and other diseases in people. The Mini Scientists then turned back to their DNA extraction activity.

Ten days in and despite daily checks, the water in the tanks became worryingly cloudy. Then an expert popped in and told me why. The fish darting and twisting above the plants were displaying classic mating behaviour and the water was cloudy as a result. A quick change of water calmed things down a little.

The fish so excelled in breeding that they are now on their way to a primary school where pupils will find out the answer to the most frequently asked question: “If a stripy fish and a spotty fish have babies, are they spotty or stripy?” I’m not sure, so I’ll leave it to the Mini Scientists to find out.

Hazel Lambert

If you’d like to read more about Mini Scientists, visit this storify of pictures and tweets from the team.

 

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