The evolving importance of DNA at Primary Level
DNA is not necessarily a subject you would associate with Primary Science. It is not specifically mentioned in the National Curriculum Guidelines and there are no questions about it on the SATs papers. Many pupils can live in blissful ignorance of the topic until at least year 8 when they will engage with it as part of their basic science instruction.
However the world is changing and so is our understanding of human biology. There is a revolution going on in the area of personalised medicine and that revolution is based on our knowledge of DNA. Already patients are being treated as individuals, cures are being developed for previously terminal diseases and hospitals are lining up to embrace the new technology. But this is just the tip of the medical iceberg.
In our quest to live longer, healthier lives we have discovered a key to unlock a potential wealth of discoveries.
That key is DNA and those discoveries are the ones our children will make.
Just as the explosion of telecoms in the late eighties and early nineties pushed ICT into secondary and then primary schools, our new found pharmacological investigations will do the same for DNA.
I think we need to steal a march on this process and start laying foundations at primary level now.
Finding the right narrative is essential to convey this information and an everyday experience will always act as better a handle on the door to new knowledge.
DNA, however, is tiny – about 150th the size of a human hair. As the driver of Evolution through Inheritance, DNA has been a contributor to the vast array of life we see on Earth today. Life that has been changing for over 4 billion years.
Furthermore, DNA is found nestles inside in a single unit called a cell. Very much like bricks are stuck together to build a house, cells are the blocks used to build us. It takes approximately 37 trillion cells to build an adult.
So we have a tiny molecule that we can’t see, connected to numbers so vast that we can’t even imagine them.
The question is, how can we use our narrative to explain the concept of genetics at all.
We must begin to weave our story by using what we can see and the subject children know most about.
DNA as the cornerstone of life
People are possibly the most complex living things on the planet.
Nine months from conception to birth is not enough to create a fully finished human. We have the longest childhood of any other animal, our immune system must continue to develop for six years after birth and we must continue growing for 18 years to achieve our final size. Instead of living within an already existing habitat, we have altered the environment to become the habitat in which we wish to live.
There are 7.7 billion people on the planet and each one of us is different (even identical twins). You can see these differences in your classroom. Who can roll their tongue? Who likes broccoli and who can’t stand it? Is anyone double jointed? Can everyone drink milk or are some intolerant?
Our complexity is the result of evolution. Our differences – or variation – the result of our genetic inheritance.
But if Evolution and Inheritance are what we see, DNA is the master puppeteer, controlling events from within. We can observe the show, but we can’t see the strings.
DNA as the most integral part of our biology
DNA – or deoxyribonucleic acid to give it is full title – is the unit of heredity. It is a collection of instructions passed from parent to child through each generation. It protects our hereditary information, so we remain similar to the parents we came from.
The well-known spiral (or double helix) shape of DNA helps protect our instructions from destruction. It serves both as shield against accidental damage and a straightforward copying mechanism, to ensure none of our vital instructions are lost.
Our instructions are made up of four individual repeating units. Each side of the spiral is like one side of a staircase, linked together by the repeating segments in between. The four units form two pairs which make up those segments. Whilst the order in which the segments appear may be different, the pairings always remain the same.
To visualise this, the class can make their own DNA double helix. Use straws, sweets or a variety of other materials (see https://www.wikihow.com/Make-a-Model-of-DNA-Using-Common-Materials for some ideas) to create the spiral shape protecting our instructions and the segments that create them. A full set of DNA instructions is 2 metres in length.
Obviously DNA is much thinner than our models could ever be, but 2 metres is still too long to fit neatly inside the cell. In order to become small enough, the DNA must coil round itself. This is easily demonstrated using a rubber band. Take opposite sides of the rubber band and twist them in opposite directions to obtain a coil in the band. Keep twisting to get a shape not unlike our DNA double helix. Continue twisting to see the coil getting tighter and smaller. How small can it get?
Knowing the shape is a great introduction to DNA, but if we don’t understand its function, there is no reason to transfer any knowledge to our long term memory.
Each person receives 3.2 billion copies of these four repeating units from their Mum and the same number from their Dad. So each parents passes on exactly half of their DNA instructions and their child is a mixture of both. A show of hands around the room will tell you which parent a child favours more. Select a specific feature. A nose, perhaps or a mouth and chin and ask the same question. Children will see they are a blend of their parents. But how?
All the information is contained in those four repeating units. Known by their initials: A, T, G, C, they constitute the four letter DNA alphabet. Just like our alphabet, these letters can be rearranged to convey a meaning.
Take the word KITTEN. This conjures up images of cute and cuddly baby cats. There are few people who can refuse such a ball of fluff and children will engage. If we alter the letter K to an M, we get MITTEN. Still potentially cute and fluffy but no longer a cat. The meaning has changed and as a result, what we do with the information will have changed too. Ideally we would cuddle one and wear the other.
The DNA alphabet works in just the same way.
We can use the instruction word GTAA as an example. Within a specific region of your DNA, this is the instruction telling your body to make lots of a pigment called melanin in the cells of your eye. It is very important as a natural, in-built sunscreen. The more melanin we have, the darker (and more protected from the sun) the eyes will be. A person with this instruction will have brown eyes.
If one of the letters was substituted, the new word (or sequence) may look like this: GTGA. This tells the body NOT to make melanin for the eyes and results in blue eyes with no sun protection.
Once we know about this DNA alphabet and how it changes, we can start to understand Evolution. A simple word puzzle explains this phenomenon extremely well in the classroom.
Offer up the word BARK. Give your class three moves to alter it, one letter at a time, to the word PANT. Each of the intermediate words must also be correct. The answer is: bark, Park, parT, paNt and illustrates how DNA sequences can change, one letter at a time, to alter one thing to another and drive evolution.
DNA works in mysterious ways
An altered melanin instruction need not confine itself to our eyes. The colour of our skin and hair is also determined by how much melanin we have.
If the change to blue eyes remained, and a further change caused something similar to happen to our skin and hair, we would have a completely different appearance. Inside we are still the same, but on the outside there is a stark contrast. We can see this contrast in the classroom. Each child will display a different combination of colouring in their hair, eyes and skin – the changes to our DNA instructions viewed through our appearance. (Note: the entire range of pigmentation we see is due to much more than just the short DNA sequences mentioned above.)
Unlike considered changes we might make when solving a word puzzle, changes to our DNA are random. They occur all the time, mostly corrected by the body. But not always. If this random change offers a survival advantage for the individual, the change is likely to be inherited by any children.
We can see this in our skin, eye and hair pigmentation.
Look at the pigmentation difference in the populations of countries on the equator in central Africa and those at the tip of the Arctic Circle in northern Europe. There is an obvious change in appearance between, for example, the indigenous people of Kenya and those of Sweden. Compare this to the hours of sunlight each country receives. You will notice that the lighter skin, hair and eye tones are more prevalent in areas where there is less sunshine and the darker shades in hotter, sunnier regions.
This change in melanin levels goes hand in hand with differences in our environment. The weaker the sun, the lighter the colour.
Sun protection is required whatever the conditions, so this doesn’t completely explain the change. We need something else.
That something else is vitamin D, essential for our growth and vitality. The sun converts this vitamin from other chemicals already available in our skin. Lots of melanin interferes with this process, making it less efficient. Once the sun became less intense, our need for vitamin D meant that we sacrificed some of our sun protection for additional vitamin production.
These superficial changes, however, do not make either the Kenyan or the Swede a different species (or type) of human. We are both the same and known scientifically as Homo sapiens. But the example highlights how change occurs together with environment. By basing our example on ourselves, children gain an understanding of how this process works. Once the basics are in place, the example can be extended to species change.
The fox is a good illustration of this. The animal is within the sphere of a child’s experience and many of the adaptations that allow these animals to survive in other habitats are obvious in their appearance.
We would expect to see the red fox (Vulpes vulpes) running around our streets after dark. Its big bushy tail keeping it warm and balanced as it forages in bins and woodland for food. Its unfussy digestive system means it can eat mice and rats for starters and the remnants of last night’s Indian takeaway as a main course. After dark it blends in with its surroundings and its ears are large enough to listen for its prey, assuming no discarded human food is at hand.
The Fennec fox (Vulpes zerda) is much smaller. With its lighter underbelly and larger ears, it is much better suited to life in the dessert. Its body has adapted to use as little water as possible, and as well as superior cooling, its large ears can pick up the slightest sounds.
A third species of fox, the Arctic Fox (Vulpes lagopus) can embrace life in the cold. Changes in blood circulation and an extremely thick coat are essential to this life. No relaxed digestion for them, either. A large portion of their diet consists of lemmings which cannot easily be replaced.
The DNA sequences of all three foxes have changed, altering the instructions within the body and producing the changes we see in each animal.
DNA as a story
Stories can bring a DNA narrative to primary education without intruding on the current curriculum or creating an additional teaching burden for staff and pupils. These visual presentations can be in the form of workshops or books. I offer both and have extended the genetic metaphor in order to engage as many children as possible.
The Dinky Amigos are cartoon characters and the DNA alphabet of ATGC morphs into Alina, Tristan, Gina and Crispin. They can be used alone or alongside other teaching to bring DNA to life. By bestowing personalities on them and anthropomorphising slightly, the chemical world of our DNA blueprint merges with the physical world of the child.
The characters act as a visual prompt for the biochemistry which underscores the entire connection and brings it into a familiar sphere, acting as a foundation for later learning. Everything is visible. There are no abstract explanations to clutter a basic understanding of the subject.
My Genetics for Kids series is designed for an upper primary audience. Narrated by Alina, the story is told from the point of view of your DNA. The basics are explained and then put into a biological context. DNA is given a function, with cause and effect clearly visible.
My DNA Diary: Cystic Fibrosis is the first story in this series and looks at how mucus is used as a cleaning fluid in your body. Changes in the DNA instructions affect this mucus and have consequences for your lungs and digestive system.
For visual learners, the concepts are summed up by colourful illustrations and a glossary lists the new vocabulary introduced within the story. For those needing a more kinaesthetic approach, there is interaction within the book and examples of the concept rooted in everyday experiences. The book is peppered with fun facts as bite-sized takeaways.
The book needs no adult guidance and can be used as a reading resource. The child can build up a genetics vocabulary that they do not remember actively learning as repetition and context are used to frame and cement the new language.
We are standing at the precipice of a medical revolution, which will shape the future in terms of health and careers. It would be remiss not to tutor our children for it. If they are to succeed and embrace the learning process needed to get there, we must open up as many avenues as we can.
Author Bio: Lisa Mullan has a Ph.D. in Biochemistry and spent several years as a training officer on the Wellcome Trust Genome Campus in Cambridge. She is now an author and science educator, bringing genetics to life in the primary classroom with the Dinky Amigos. https://www.dinkyamigos.com