CRISPR Gene Editing Teach-Out

In this lesson, we briefly explain the underpinnings of CRISPR and its relation to gene editing. This is the most technical part of the Teach-Out, and is not a required reading. You may decide to move on to the next lessons where experts explain CRISPR in varying degrees of complexity; your learning experience will not be compromised. We recommend you watch one of the four introductory videos in the Explanations of CRISPR reading as a starting point. Later in this Teach-Out, when you gain more knowledge about CRISPR, you may return to this lesson to review this section.

What are genes, genomes, and DNA?

As you’ve heard, CRISPR is a type of gene editing, or genome editing, technology. A genome is the sum total of an organism's genetic information, everything needed to let it grow and develop. Genes are smaller pieces of genetic information. Whether we refer to gene editing or genome editing tends to reflect the size of the edit.

The building block of genes and the genome is a long molecule called Deoxyribonucleic acid, or DNA for short. The DNA molecule consists of two strands, each containing sequences of four bases–Adenine, Thymine, Cytosine, and Guanine– located on a base made of sugar-phosphate (Figure 1 DNA-Base-Pair). These four bases, or nucleotides, pair up by hydrogen bonds across the two strands. The two paired strands of DNA twist and form a double helix (Figure 2 DNA-Double-Helix). DNA molecules carry the instructions for living organism cells to produce proteins with different functions and to give living organisms distinct characteristics such as different types of tails in cats or varying height in human beings.