7. DNA and Genetics
Take a look at yourself in a mirror.
- What colour eyes do you have?
- Do you have freckles?
- Is your hair straight, wavy, or curly?
Then think about your likes and dislikes.
- What is your favourite animal?
- Do you prefer reading a book or running races?
Now think if you know anyone who is exactly the same as you. There won’t be!
You are unique - there has never been, and never will be, anyone who looks, thinks, and behaves exactly like you. However, at the same time you might look very similar to people in your family.
- Do you have the same colour hair?
- Are you all right or left-handed?
- Can you all roll your tongue?
These similarities or differences between you, your family, and every other human are determined by your genes (pronounced like “jeans”) and studied in a type of science known as genetics.
Everybody has thousands of genes, which are tiny molecules found inside you that contain the information needed to make you. You have genes that determine how you look, such as your hair colour, height, whether or not you have freckles, and much more. Half of your genes come from one biological parent and half come from your other parent. This means that you will have characteristics of both your parents, and, through them, characteristics of everyone else in your family (as your parent’s genes come from their parents, your grandparents). These physical characteristics are known as inherited traits. However, you are far more than just how you look. You also have many things that you have developed as you have grown up. These include things like your favourite food, whether you like cats or dogs, if you can play a musical instrument, and more. These traits are probably different from your brother’s or aunt’s or great-gran’s. This is because they are not determined by your genes, but are instead are learned. Therefore these are known as learned traits. Your combination of learned and inherited traits is what makes you special.
Complete the activity sheet to help you think about what kinds of traits are learned and which are inherited from your parents, and then what traits you share or are different to your family members and friends.
Genes are made of DNA. This DNA is in a helix structure which looks like a twisted ladder. The rungs of the ladder are 4 different molecules known as “bases”:
- Adenine (A)
- Guanine (G)
- Cytosine (C)
- Thymine (T)
This structure of DNA is the same for every living organism, from plants to fish to spiders, but the order of the bases along the ladder is unique to each person.
It’s similar to your phone number: all telephone numbers are made up of the same individual numbers but in a unique sequence that defines each phone.
You can make a model of this structure, and even extract DNA using household materials by following instructions found at:
More information can be found at:
PhD Student at Gram Hansen Laboratory, Centre for Inflammation Research, University of Edinburgh
"I am currently in the second year of my PhD in Tissue Repair and Regeneration. This involves looking at the link between cancer and the body’s natural regenerative processes. Current cancer treatments like chemotherapy work by killing cancer cells, but they also kill cells that can regenerate. This results in the nasty side effects seen in chemotherapy - such as hair loss and reduced immune system function. Therefore, I am trying to work out how we can make better cancer treatments without these side effects by using gene editing. This alters genes associated with increased cancer risk, and lets me study what affect this has on regeneration."
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