What is DNA? What is a Gene?

DNA, or deoxyribonucleic acid, is basically the instruction manual for life. It's found in almost every cell of your body (red blood cells are the exception!), and it tells your cells how to grow, develop, and do their jobs.

DNA looks like a double helix, and it’s made from four chemical building blocks called nucleotides:

A - adenine

C - cytosine

G - guanine

T - thymine

The specific sequence of A’s, T’s, C’s, and G’s is what gives the instructions, and variations in which nucleotide base is in a specific spot are what make us each unique.

A gene is a smaller section of that DNA. You can think of DNA as a big cookbook, and each gene is like an individual recipe inside it.

Each gene carries the instructions to make a specific protein. And proteins are the things that actually do stuff in your body—they provide structure, act as enzymes, regulate hormones, do cellular functions.

A genome is the complete set of DNA in a cell. It contains genes (around 20,000) plus segments that control how the genes are expressed. Gene expression refers to the process by which the gene is translated and transcribed into a protein. There are multiple ways that cells can control which genes are 'turned on' for transcription and also when and how the transcribed mRNA is translated into the protein.