Understanding Genetics: Four Letters Which Create Everything

When we talk about our genome, we are referring to all the genetic material in our bodies, and we hold a copy of our genome in almost every healthy cell in our body; to give you an idea of how much DNA that is…if we were to uncoil all the DNA in one human body, it could stretch from the earth to the sun 600 times! Mind blowing, eh?!

DNA or Deoxyribonucleic Acid is the chemical found in the cells of plants and animals that carries genetic information. DNA is made up of four base chemicals: Adenine (A), Thymine (T), Guanine (G) and Cytosine (C). Humans typically have 46 chromosomes which are arranged in pairs with 23 chromosomes inherited from your mother, and 23 chromosomes from your father. Each chromosome in the pair has the same set of genes which correspond to one another. However, there may be one or more forms of these genes, known as alleles. Therefore, whilst we all have blood, we have different blood types. And maybe a bit gross, whilst we typically have earwax, someone’s earwax may be wet, and someone’s drier. Alleles can be dominant or recessive, and it is this pattern which determines which of the alleles will be expressed. This explains why we have the same general structure: head, hair, eyes, ears, heart, lungs etc., but we then have variations within each category.

But how on earth do we translate a DNA sequence into traits and characteristics? It’s all to do with proteins. Now, I’m not talking about proteins in the classical sense of chicken breast or tofu, but I am instead talking about protein molecules, made up of long chains of amino acids.  These proteins are working constantly to, for example, break down food, move your muscles, grow your hair, skin and nails, and control physiological processes for growth, development, metabolism and reproduction. But the creation of these proteins is all down to our DNA.

Protein synthesis in its simplest form happens in 2 stages. Whilst, in reality, protein synthesis is occurring constantly in every chromosome in every cell, to explain the process, we need to zoom into a single gene: first through ‘transcription’ DNA is ‘unzipped’ to expose the base chemicals; then through binding, a complimentary copy of the gene code (called a messenger RNA (mRNA) molecule). The second stage called ‘translation’ where the duplicate molecule is translated into a sequence of amino acids which combine to make a protein.

Basically, proteins are the building blocks of our bodies, and our DNA is used to create every single molecule. If you think this same protein synthesis process is happening constantly to control every aspect of our body, you get some insight into how incredibly complex and clever our bodies are, and in turn how incredible broad and deep the science of genetics is.

References

https://www.nigms.nih.gov/education/fact-sheets/Pages/genetics.aspx

https://www.cdc.gov/genomics/about/basics.htm

https://www.bbc.co.uk/bitesize/guides/z36mmp3/revision/1

https://www.khanacademy.org/test-prep/mcat/biomolecules/dna/a/dna-structure-and-function

https://www.thesciencehive.co.uk/dna-replication-transcription-translation-a-level

https://basicbiology.net/micro/genetics/transcription-and-translation

https://en.wikipedia.org/wiki/Protein

Disclaimer

The information in this blog is for information and entertainment purposes only. I am not a medical professional, so I have never and will never give medical advice in this blog. You should always speak to a healthcare professional about your unique health needs. My opinions are entirely my own and do not reflect the organisations or people I work for. I only discuss published literature in this blog which are referenced with links.

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