The Magic School Bus + Rides Again Wiki
The Magic School Bus + Rides Again Wiki

[[Waste Not, Want Not|Waste Not, Want Not]] Janet's Mystery Gene [[Making Magic|Making Magic]]

Janet's Mystery Gene is an episode of the second season of The Magic School Bus Rides Again.


Carlos is assigned to read to the kindergarten class with, to his chagrin, Arnold's nervous cousin, Janet, who wishes to regail the kids with a telling of her autobiography, Janet: The Untold Story Finally Told. She reads the kids a sample of the first chapter: "Why I'm Better than Everyone" : "It was a perfect spring day, when Janet 'Awesome' Perlstein was born," she reads. Ralphie tells Janet to "have a heart", and Janet responds by turning to another chapter in her book, titled "I ❤ Me", saying "you can see it for yourself." Ms. Frizzle enters the room riding a mini-train and proposes a field trip inside Janet's heart. The other students are up for it, so they enter the Magic School Bus, with Liz staying behind with Janet, just like with any human body episode. The Bus shrinks, turns into a cell, and approaches Janet. She warns the kids to "look, don't touch" and to stay out of her left ventricle. "Plus no food, drink, flash photography, and-", she says, but before she could continue, the Bus speeds into her.

Inside Janet, Ralphie says she does have a heart, but Jyoti points out there must be something that makes Janet the way she is, prompting Ms. Frizzle to go deeper. The class gets smaller and smaller and smaller until they reach Janet's chromosomes, which Ralphie points out as "mutant worms from the planet Yuck". After learning about the fact that chromosomes make up who we are, Carlos says that there must be something that makes up Janet's nervousness. The kids go inside Janet's chromosome and reach her DNA. The kids learn about the properties of DNA, from its long name (deoxyribonucleic acid) to its double-helix shape, prompting Carlos to tell everyone that a "nervous gene" might be inside this DNA. They enter the Bus, transformed into a DNA train that Ms. Frizzle names after the genetic lab CRISPR, and Ms. Frizzle teaches the kids about the nitrogenous bases of DNA, adenine, thymine, cytosine and guanine. Ms. Frizzle drives the Bus along Janet's DNA, as they come across genes that make up her eyes, hair, and ingrown toenail, which Arnold says runs in the Perlstein family. He shows his ingrown toenail, grossing out the rest of the class. Carlos starts the DNA editor feature on the Bus, which he thinks will change Janet's nervousness.

Impatient, Carlos speeds up the bus, causing damage to Janet's DNA. The DNA recombines itself but causes physical changes to Janet, first her hair color from red to black, then her nose and ears, and ultimately what kind of species she is: a plant, cat, penguin, a Komodo dragon- all because of the fact that DNA has the code for anything that is living. Carlos wonders why he can't stop the CRISPR Express, and Ms. Frizzle replies that the Deaccelerator, the machine that will stop it, is in the auto-parts shop.

To repair her DNA, the class samples Arnold's hair and uses its DNA as a template to fix Janet. They manage to repair her but end up giving her freckles, which turns out to be a dominant genetic trait. After discovering why and repairing the mistake they return to the bus and watch the outcome. Her freckles are gone, but somehow, Janet ends up with a deep, threatening voice, because they used Arnold's DNA. They have to start over. Just as Janet enters the kindergarten classroom, transforms into a monkey, which the kids cheer in excitement at. Eventually, they completely restore Janet's code, normal voice and clear skin in all.

Carlos abandons the search for Janet's nervous gene and returns to stop Janet from reading her autobigraphy. Janet scolds him for being late and Carlos confesses about the mission to find her nervous gene and replace it with a nice gene, which leaves Janet non-plussed. She scoffs at Carlos, stating that a nervous gene is nonsense and that she didn't get nervous until a certain embarrassing point in her life. Carlos realizes that Janet's nervousness was simply a culmination of her experiences. Instead of her autobiography, Janet adlibs a story about Carlos, but to Carlos and the class' surprise, she manages to be nice to the kids.

Ultimately, the kids loved Janet and she is seen being chased by them, wanting to hug her. Nervous as she is, she runs from them.


  • Janet turning into an aardvark wearing glasses and carrying a book is a possible reference to Arthur Read from Arthur, another show that debuted during the third season of the original show, and whose "viewers like you" card was very popular to use, even in other PBS shows like the original Magic School Bus.
  • As this episode focuses on Janet, many things were revealed about her:
    • She is right-handed.
    • She is lactose intolerant.
    • She has an ingrown toenail - which runs in the Perlstein family.
  • Wanda is revealed to have a pet cat.
  • This is the last episode to focus on Carlos in this season.
  • This is the last episode to feature any of Ms. Frizzle's Class' relatives, in this case, Janet.
  • This is the last and only appearance of Janet in this season.
  • Tim and The Talking Trees, I Spy with my Animal Eyes, and The Land Before Tim were referenced in this episode when Carlos explains his recent genetic mutations into a fir tree, fossil, and butterfly.


  • Janet's freckles are removed in this episode as a plot point, but they appear again briefly at 7:04 (on versions with the Netflix logo and A Netflix Original byline) before Ms. Frizzle and the class begin making changes to her DNA.
  • Janet was implied not to have freckles in this episode, similar to her appearances from Gets Lost in Space to Makes a Stink. But in other episodes of this series' first season, she did have freckles.
  • When Ms. Frizzle pulls the Mesmerglober lever on the bus, she wears her math-themed dress from Ralphie and the Flying Tennellis instead of the genetics dress.