This news story describes a phenomenon that illustrates how traits are randomly passed from generation to generation. A photo in the story shows two young women whose physical traits are so different from one another that most people would say they are not related. The photo shows seemingly unrelated ladies that are not just related, but are twins. The video linked below tells the story of these two women to add additional information for the phenomenon without explaining the how and whys.
Either the video or photos can be used to engage students in thinking about variation of inherited traits. As a start, these photos can be provided to the students for their observations of variation in twins. Students can then explore genetics to explain how these young women can exhibit such different traits, even when they have the same parents.
This phenomenon could stimulate the following driving questions:
1. How can these twins look so different?
2. Why do some siblings look more similar than non-siblings?
3. How do chromosomes and genes play a role in the genetic variation of offsprings?
A video is also available for background information: https://www.youtube.com/watch?v=JIUK2KSbvvI