Sophie tackles the question of why there are so many different breeds of dogs. She briefly discusses the history of dogs and discusses how genetics makes dogs different and why some breeds are better suited for certain functions.

Scientists have sequenced the tomato genome because the taste, size, color and more of a tomato is determined by their genes.

Peter gets home after being bitten by a genetically-engineered spider during a school field trip. He falls ill from the spider's venom, and while he's asleep the venom alters his genetic makeup. He wakes up to find his body has changed dramatically overnight.

Homer brings together relatives from the tri-state area in an attempt to prove to Lisa that there are no problems with the genes in the Simpson family. When he fails to prove the success of his relatives, Marge suggests he ask the women instead of the men. The women are successful, and they state that the defective Simpson gene affects only the men because it is on the Y chromosome. Important to note is that some common, real-life defects and deficiencies occur more frequently in men because they have only one X chromosome, not because the defective gene is on their Y chromosome.

A trip to a cell to hunt for DNA teaches the StoryBots about how DNA is structured with Ms. Polymerase.