Basics of Human Genetics
Welcome! I'm really looking forward to exploring the world of genetics with you today. Before we jump into how our physical traits are programmed, I'd love to know what brings you here and what your background looks like.
I'm a complete beginner, just curious about how DNA and heredity work!
It is wonderful to have you here! Genetics is an incredibly beautiful subject to dive into, especially because it serves as the ultimate instruction manual for who we are.
To kick off our journey, let us zoom all the way down into the microscopic heart of your cells. At the very center of almost every single cell in your body, there is a master library containing a blueprint. This blueprint is , which stands for deoxyribonucleic acid.
Think of DNA as a highly organized recipe book. The pages of this book are made of tiny repeating chemical units called nucleotides. Every single nucleotide has a specific "letter" attached to it: A (Adenine), T (Thymine), C (Cytosine), and G (Guanine).
These four letters work exactly like the 0s and 1s in computer code. The specific order or sequence of these letters is what writes the instructions for building and running your entire body.
A double helix structure of DNA showing antiparallel sugar-phosphate backbones and complementary base pairs.
As you can see in the visualization, DNA does not just float around in random single letters. It forms a gorgeous, twisting ladder called a double helix.
The rungs of this twisting ladder are made of our four letters pairing up with each other across the gap. But they are incredibly selective: A always pairs with T, and C always pairs with G. Because of this rule, if you know the letters on one side of the ladder, you can easily figure out the letters on the other side.