The Code Breaker By Walter Isaacson

The Code Breaker By Walter Isaacson
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Extremely fascinating. Provides excellent insight into the world of gene editing. Isaacson does a great job keeping the book interesting and poses extraordinary questions regarding the morality of gene editing.

At the beginning of the book, we are introduced to Jennifer Doudna, a 12-year-old girl who has an infatuation with science. Isaacson describes that Doudna read The Double Helix By James Watson, a book that details the discovery of the structure of DNA. Doudna thought that the book resembled a mystery and that the scientists were like detectives, tasked with uncovering the secrets of DNA. Doudna loved the role that Roslin Franklin played in the discovery, as it showed her that women could be scientists too. It was this book that sparked her passion.

Doudna would go on to earn a doctorate in chemistry. Doduna became fascinated with the molecular structure of DNA. After meeting French scientist Emmanuelle Charpentier, Doudna now had a partner to tackle this unknown abyss that is DNA structure. It was soon not long until the women became obsessed with learning how CRISPR (a technology that microbes used to fight viruses) functioned. Doudna and Charpentier soon figured out that the key to understanding CRISPR was in the under-appreciated sister to the DNA molecule, RNA. Now I would not do this groundbreaking technology justice if I tried to explain it myself, so here is a portion from the CRISPR Therapeutics website that explains the technology.

CRISPR Lexicon

  • CRISPR: Clustered Regularly Interspaced Short Palindromic Repeats of genetic information that some bacterial species use as part of an antiviral system. A group of scientists, including our co-founder Dr. Emmanuelle Charpentier, discovered how to use this system as a gene-editing tool (Jinek, et al. Science 2012)
  • Cas9: a CRISPR-associated (Cas) endonuclease, or enzyme, that acts as “molecular scissors” to cut DNA at a location specified by a guide RNA
  • Deoxyribonucleic acid (DNA): the molecule that most organisms use to store genetic information, which contains the “instructions for life”
  • Ribonucleic acid (RNA): a molecule related to DNA that living things use for a number of purposes, including transporting and reading the DNA “instructions”
  • Guide RNA (gRNA): a type of RNA molecule that binds to Cas9 and specifies, based on the sequence of the gRNA, the location at which Cas9 will cut DNA

Three main categories of genetic edits can be performed with CRISPR/Cas9:

CRISPR/Cas9 Gene Editing



If a single cut is made, a process called non-homologous end joining can result in the addition or deletion of base pairs, disrupting the original DNA sequence and causing gene inactivation



A larger fragment of DNA can be deleted by using two guide RNAs that target separate sites. After cleavage at each site, non-homologous end joining unites the separate ends, deleting the intervening sequence



Adding a DNA template alongside the CRISPR/Cas9 machinery allows the cell to correct a gene, or even insert a new gene, using a process called homology-directed repair

Source: edits genes by,revolutionary technology into transformative therapies.

Long story short, the technology allows for the possibility that genetic material can be edited. For instance, a certain gene that could put someone at a higher risk for cancer could be removed. The book also touches on the other, more concerning aspects of gene editing, like the idea that babies could be aesthetically edited to the parents liking. Isaacson also details Doudna's fear about the technology potentially being used as a bio-weapon. These questions about the morality of gene editing are really the highlight of this book. There are so many benefits of this technology along with so many risks. Towards the end of the book, Isaacson says he agrees with Doudna's view that gene editing should be pursued, but that checks and balances should be put in place to make sure the technology doesn't fall into the wrong hands.

A Photo of Jennifer Doudna Image Credits

My only gripe with "The Code Breaker"  is that it is very long and sometimes overly detailed. If you are not interested in the technology of CRISPR from the beginning, then I don't recommend that you continue through the rest of the book. If the technology interests you, then these long and overly detailed sections will serve only as a minor inconvenience to the otherwise groundbreaking technology. If you have some sort of fascination with science, then I don't see why you won't enjoy "The Code Breaker". It really does educate people on this new and emerging technology, which hopefully could be extremely important in the future.



Book Length-7/10

Writing Style-9/10

Cumulative Score-33.5/40

Stay tuned for my next review, the book that I am reviewing is an amazing read!

The Code Breaker By Walter Isaacson

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