To Catch a Thief by Mandy Hartley

Author:Mandy Hartley
Language: eng
Format: epub
Publisher: G2 Rights Ltd

“What’s a filter?” Annabelle showed Harry the special tubes with the filter inside which looked like a very small piece of paper. She transferred the liquid from the first set of tubes into the filter.

“A filter is like the sieve Mum puts flour in when she makes cakes to get the lumps out. All the broken up bits of cell get caught in the sieve. The DNA which is dissolved in the liquid goes right through the sieve. Harry watched as a clear liquid slowly dripped out of the bottom of the filter and into another tube. They waited patiently until it had all collected in the bottom of the tube.

“Now to add the alcohol!” said Annabelle. Harry felt his nose tingle as Annabelle added the alcohol. The smell was really strong.

“The salt in the DNA extraction buffer we added at the start makes the DNA clump together and the alcohol makes the DNA come out of solution. If you watch the tube as I tip it gently up and down you will see the DNA appear,” explained Annabelle. “There it is! Can you see the white strands?” Harry watched as the two liquids swirled together like ice cubes melting into water. Then suddenly very thin strands like white cotton appeared. It was so exciting. One minute the tube contained only a clear liquid, the next what looked like a ball of white cotton appeared as if by magic!

“How cool is that? Look Annabelle – we have DNA in all our samples. That’s amazing!” Both children were delighted. Their eyes sparkled.

“We just have to hook the DNA out with this little plastic hook and put it in this last liquid. This will make sure the DNA is really clean and it can be stored for a long time without being destroyed. If we leave them in the fridge Mum will think they’re her samples and will get the results for us. We are finished Harry!” The children quickly cleaned up making sure they left everything as they found it. They ran out of the laboratory and into the lounge to check on Granny. She was still asleep!

“I wish Mum would come home soon so we can get the results. I just hope they’ve worked,” whispered Annabelle to Harry. Both children crossed their fingers.

When Mum and Dad returned later that day Mum proudly announced “I’m going to take the rest of the day off. No lab work till tomorrow!” Annabelle looked at Harry and could see he was as disappointed as her.

“We really need those results” said Harry.

“I know, but hold on a minute,” said Annabelle. “Maybe the delay could be just what we need.” She suddenly looked very pleased with herself.

“I don’t understand,” said Harry.

“Well, I just had a thought. If we could get some fur from Issy and Peter’s dogs Scally and Poppy and from Milly we could get DNA from them. If we got DNA from the fur we found in the shed and compared them then we

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