No biology background needed
Learn gene editing, from zero
A ladder of short guides: what DNA is, what a gene is, how CRISPR finds and changes a sequence, and then the advanced methods that came after it. Read in order or jump anywhere.
24 guides. Each one opens with a plain-language answer, then goes deeper. Analogies are used freely — and every analogy comes with a note on exactly where it stops being true, because a half-understood analogy is how most misconceptions about this field start.
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Start here
The vocabulary everything else depends on.
Guide · 4 min read
What is DNA?
DNA is a long chemical chain that stores the instructions for building and running a living thing, written in an…
Guide · 4 min read
What is a gene?
A gene is a stretch of DNA that carries the instructions for making one particular thing the cell needs — usually a…
Guide · 3 min read
What is a chromosome?
A chromosome is one very long DNA molecule packaged with proteins; humans normally have 46, in 23 pairs.
Guide · 3 min read
What is a genome?
A genome is the complete set of genetic instructions in an organism — every chromosome, every gene, and everything in…
Guide · 3 min read
What is RNA?
RNA is DNA's working copy — a temporary, single-stranded version the cell makes when it needs to use a gene.
Guide · 5 min read
What is a mutation?
A mutation is a change in DNA sequence. Most do nothing, some cause disease, and a few are beneficial.
Guide · 5 min read
What is gene editing?
Gene editing is changing the DNA sequence already inside a living cell, at a chosen location.
Guide · 6 min read
What is CRISPR?
CRISPR is a bacterial immune system that scientists reprogrammed into a tool for finding and changing a chosen piece of…
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CRISPR basics
How the system actually works, step by step.
Guide · 6 min read
How CRISPR works, step by step
A guide RNA finds the target, the Cas protein cuts, and the cell's repair machinery makes the actual change.
Guide · 4 min read
What Cas proteins do
Cas proteins are the machinery of the CRISPR system: they carry the guide, search the genome, and cut what matches.
Guide · 4 min read
What guide RNA does
The guide RNA is the address. It carries a short sequence matching the target and holds the Cas protein in place.
Guide · 5 min read
How cells repair DNA — and why it decides the edit
The cell, not the editor, makes the change. Which repair pathway it uses determines what you actually get.
Guide · 5 min read
What off-target editing means
An off-target edit is a change made somewhere other than the intended site, because the guide tolerated a mismatch.
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Intermediate
What editing can do to a gene, and how it is delivered into a body.
Guide · 5 min read
Knockouts, insertions and deletions
The three basic things editing does to a gene: switch it off, take something out, or put something in.
Guide · 6 min read
Delivery: the real bottleneck
Getting the editing machinery into the right cells, in enough of them, without harm — the problem that decides which…
Guide · 5 min read
Ex vivo and in vivo editing
Ex vivo means editing cells outside the body and putting them back; in vivo means editing them where they are.
Guide · 5 min read
Viral vectors
Modified viruses used as delivery vehicles — very good at getting inside cells, which is exactly what they evolved to…
Guide · 4 min read
Lipid nanoparticles
Tiny fat bubbles that carry genetic cargo into cells — the delivery technology that made in vivo CRISPR possible.
Guide · 4 min read
Turning genes up and down
Changing how loudly a gene is expressed, without changing a single letter of its sequence.
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Advanced
The methods that came after Cas9, and where the field is going.
Guide · 4 min read
Multiplex editing
Making several edits in the same cell at once — necessary for cell therapy, and riskier than making one.
Guide · 4 min read
CRISPR diagnostics
Turning CRISPR's habit of chopping up nearby nucleic acid into a fast, cheap test for a specific sequence.
Guide · 6 min read
Why gene therapies cost millions
The economics of a one-time treatment for a small population — and why the arithmetic that produces a $2.2 million…
Guide · 5 min read
How a gene-editing company works
What a pre-revenue biotechnology company actually is, and which numbers describe it — information, not investment…
Guide · 6 min read
How to read a clinical trial result
What a Phase 1 result does and does not tell you, and the questions worth asking before you believe a headline.
