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  • Writer's pictureSinead Mackintosh

Back to Basics: What on Earth are Genes?

I am sure you have heard the terms “genes” or “chromosomes,” but maybe you are not 100% sure what they actually mean. Well, let’s start at the basics. (1.) Inside every cell in your body there is a nucleus, and this houses the genetic information that tells your body what to do, whether it says to make green eyes and brown hair or blue eyes and black hair etc. (2.) This information is neatly stored away in chromosomes, which are portrayed as long finger like things. The chromosome is just the double-stranded helix shape that has become so iconic across the board. (3.) This helix is itself made up of nucleotide base (A, T, G, C) pairs (just fancy chemical structures) that pair off to create genes. So, if you have green eyes, the gene coding sequence could be ACTAGCTA, whereas blue might be TCATGTACAG and that what makes your eyes look different. We can go into more detail on that later on because this is just the start. You get half of your chromosomes (humans have 46 in total) from each of your parents, and they “pair up” so that you have two similar chromosomes in a pair and they are conveniently numbered from largest to smallest (numbers 1-22), and then the sex chromosomes (X and Y) are labelled as such. Changes can occur in the sequences, generally called mutations, and that can have no effect or a wide range of effects depending on the type and size of the mutation. Some mutations can lead to cancer, and the chemicals or causes of the mutations are called carcinogens. You may have heard of that, and I will explain cancer in another blog post soon!

So, the take-home message is that in each of our cells, we have a complete copy of our genomic information in the form of chromosomes. The sequences that make up the chromosomes differ from person to person and make us all unique! 

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