The aim of this session is to demonstrate novel techniques for teaching Primary and Secondary students about inheritance, in the context of Forensic Science and real life applications to solving crimes.
The workshop is based on research being conducted by scientists at the Earlham Institute. One of the problems faced by forensic scientists is accurately analysing data which contains DNA from more than one person.
For example, if someone has been stabbed, there will be epithelial/blood cells from the suspect on the knife. However, if a victim has bled, these cells will be outnumbered by cells from the victim. This makes analysis difficult. Researchers are using a cell sorting machine to collect individual cells from the evidence. The students will have a go at this and compare the results, to existing analysis techniques.
The workshop starts with the crime - “Murder at the Boutique Hotel” (Secondary), “Pizza Thief at the Boutique Hotel” (Primary). Initially, they must think about where the evidence will be at the crime scene. We talk about cells, organs, and organ systems and where cells are in the body. We think about where the suspect will have touched as they move through the hotel, “Every contact leaves a trace”. I have a Lego model of the Hotel and crime scene. Students must add crime markers to indicate where we are most likely to find DNA evidence.
I demonstrate how DNA is extracted from the samples. I show the students the cell sorting machine the scientists use, then they use my mini cell sorters, to manually separate blood and epithelial cells. The suspect epithelial cells they collect glow in UV light. The students place these in their dark rooms to see how many epithelial cells are from the suspect. We then move on to the analysis.
The students are shown a DNA profile. I explain to them how the DNA profile is generated. To understand it they learn about microsatellites, which have different repeat numbers. We use a simple demonstration of a sentence, “The Cat Sat on the Mat,” to show this. I then demonstrate why for each part of the DNA on the DNA profile there are two numbers. One is inherited from Mum, the other from Dad. I use baubles and limbo poles to explain this! This is the section that teachers will really love. It is a great visual way of getting children to see exactly how genetic information is inherited.
Another set of poles is used to demonstrate what happens currently when we analyse a mixed DNA profile (DNA from two people). We talk about homozygote and heterozygotes, and how we use this information to analyse the data. Students compare their data, with data from the Research Scientists new technique. The students can see how this new technique could revolutionise analysis of mixed DNA profiles! We identify which student is the murderer/thief and they are arrested.
The outcome is that teachers will have a tool box of practical demonstrations they can use to teach students about inheritance in way that they can understand, engage with and understand the importance of what they are learning in application to real life science.
