Genetics are what makes you, you. They dictate everything from your eye colour to whether you’re a human or a T-Rex (imagine having tiny arms and a massive head like that when you’re trying to take a selfie).
Genetics are also a group name for our genome which is like a biological computer code that tells our genetics what they are and what they do and the genome, in turn, is made from our DNA. The very bare bones of every almost single living thing, even some viruses have DNA, and some have RNA which is like DNA but made up slightly different and I’ll cover the differences later on for you.
DNA stands for DeoxyriboNucleic Acid but since trying to remember how to spell that would be a pain it’s just called DNA. Now Although DNA is tiny, it’s made up of even smaller bits called bases, more specifically Adenine, Thymine, Guanine and Cytosine. These then join to a phosphate-deoxyribose backbone, which is the bit that runs up and down the edges. It then forms a twisty ladder shape called a double helix; deoxyribose is a sugar, not the sweet kind but a different chemical sugar, and the phosphate is the molecule that joins it all together like superglue. If you’re not sure what a double helix looks like, then I’ve included fun and more importantly tasty model you can make at the end of this page.
Now, all this had to be discovered before we could do anything with it and although DNA was isolated by Friedrich Miescher in 1869, it wasn’t until 1943 that they thought maybe it had something to do with genetics, and this was later confirmed in 1952. The 4 bases were first isolated in 1878. In 1919 they fully identified by Phoebus Levene – a strange name I know but in 1863 when he was born Nehemiah, and Garibaldi were common names. There was a ‘race’ by various university research labs to pin down the full structure of DNA after William Astbury produced the first diffraction patterns in 1937. This was finally done by James Watson and Francis Crick in 1953 with their suggested model being based on an X-ray diffraction image taken by Rosalind Franklin and Raymond Gosling. Crick later also worked on the relationship between DNA and RNA as well as proving that genetic code is based on a set of 3 bases called codons.
Since all this happened, we have made leaps and bounds and in 2003 the human genome was sequenced. The human genome is basically the recipe for a human and is made up of 3 billion base pairs, that’s 1 billion codons and 6 billion single bases. Sometimes it’s hard to imagine numbers that big so to put it into context, imagine 217 football fields filled with skittles; that’s enough to give even Scooby a stomach ache.
In humans all this DNA is held within our 23 pairs of chromosomes which are located in our cells nuclei (plural of nuclei). These chromosomes are a mix from your parents and determine what eye and hair colour you have along with other things like how tall you’re going to be or if you’re going to be more inclined to develop certain disorders like asthma. When the cells split to give us new cells and when we grow the chromosomes split as well in a process called Mitosis which I’ll cover later on when I go into how our cells work.
Look out for more from me to find out how your genetics determine the things above using your chromosomes and I’ll also be continuing my infectious disease series.
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