Baking, Building, Blending: Explaining genomics using analogies

So when we talk about genes and genomes, it can sometimes get confusing for students. So if you can visualise these concepts, it can really help. In this video, we’re going to show a few different analogies that we often use to explain genes, genomes, cells, and their structure.

So fundamentally, our genome is a set of instructions. And over the years, I’ve heard lots of different ways of explaining this. So from a blueprint, to a Haynes manual for all you car-lovers out there, to an instruction book. But I think our favourite has to be the recipe book. Our recipe book is analogous to a genome, which is a complete set of instructions that makes up an organism. And we can break that down further into genes that create proteins. So if we focus in on our recipe book, we can hone in on a specific page. And that is a specific recipe for a specific cake. In this case, a fairy cake. This is analogous to the level of a gene.

A gene contains a specific DNA to make one specific product– a protein. We can also use this analogy to help students understand the effects of mutations at the gene level on our protein product. So we are going to make a basic fairy cake. So to do this, we need self-raising flour, we need sugar, butter, two eggs, and a little bit of vanilla extract. We mix them all together in the bowl, and that will produce– Our basic fairy cake, which is analogous to our protein. But what if something changes? So for example, what if I accidentally use salt instead of sugar? It’s going to produce the same fairy cake. But I’m not going to eat that. That’s not edible.

This is analogous to a loss-of-function mutation. So maybe our protein had a mutation that didn’t change how it looks on the outside, but it might change how it behaves in the cell. What if we add something? So for example, I could add some cocoa powder. And this will, again, produce a fairy cake. It will be edible. But it will probably look a little bit different and maybe taste a little bit different. We can use this as an analogy for gain-of-function mutation. The protein might still be able to do its core jobs, but it might have also gained some new jobs as well. This is often how new genes evolve. Sometimes a gene might be duplicated within a genome.

And that second copy might go on to gain some new functions that might be beneficial to the cell. There’s lots of other ways you can use this analogy to help your students understand genes, genomes, and proteins. So have a think about that, and let us know your ideas in the discussion box below.

In this analogy, we’re going to show how we use LEGO to describe genome size and cell structure and function. And who doesn’t like using a little bit of LEGO? Now, LEGO can be really useful for talking about things like genes and genomes. So a little bit like our recipe book earlier, we can see LEGO as an instruction book. So for a really complicated structure like a boat or an X-wing, you need a lot of books of instructions. But a slightly simpler version like this, perhaps you just need a few little instructions in a book like this. This is analogous to our whole genome.

So in the human genome, we have 46 chromosomes, which we could think about as different books as part of our genome. In comparison, the Aedes aegypti mosquito, which is the vector for yellow fever only has six chromosomes. It’s worth noting that complexity of life isn’t as simple as the size of an organism. For example, the animal with the most chromosomes is a butterfly called the Blue Atlas with a whopping 450 chromosomes. It’s not just genome size that we can use LEGO to help explain. We can also use LEGO when we’re talking about cell structure and function. So if we use this example here, we’ve got an eagle.

But this could be an organism, it could be an organ, it could be a piece of tissue. And by looking at it, you can see that it’s made of different shapes, and size, and coloured blocks. In the same way, our human body isn’t just made up of one type of cell. In the human body there’s about 250 different types of cells. And one project that’s seeking to understand all of these is the Human Cell Atlas. So we often use LEGO to help students understand that different types of cells have different structures and functions within a larger organism. So the Human Cell Atlas uses something called single-cell sequencing. And again, LEGO can be used to explain how that works.

So what you can essentially do is take your LEGO structure. This could be a tissue, which again, you can then deconstruct into its component parts. So from this eagle, we can tell that it’s made of brown blocks, yellow blocks, and white blocks. But they’re all slightly different. So a bit like the cells in a tissue, they’re made of different components. This is a little bit harder to do in real life with a real tissue sample. And so, we’re going to show you another analogy in a second that helps explain this to a slightly higher level.

In the last analogy, we introduced the concept of single-cell sequencing. And now, we’re going to use a different analogy to help students understand how powerful a technique this is. So in this glass, we have a smoothie. It’s red. It smells nice. But how can we tell what’s actually gone into it? So if we were able to use single-cell sequencing on our smoothie, we’d essentially be able to un-make a smoothie. We’d be able to take our smoothie and make it back into its constituent parts to help us understand that there’s one banana, one apple, a handful of strawberries, and half a pineapple in it.

In the same way with a real tissue sample, single-cell sequencing can take a tissue sample that contains lots of different types of cells and help us understand exactly what cells are part of that mixture. It’s a really powerful form of next generation sequencing. Well, hopefully by now we’ve shown you a few different analogies that you can use to talk about DNA, genes, and genomes, and even sequencing technologies. I hope you’ve enjoyed watching the analogies. And please do try them with your students, and let us know how you go on.