Next, we transitioned in to the lesson about Down Syndrome. We discussed the first three slides of the Down Syndrome Case Study slide deck and then detoured to the Wikipedia entry on aneuploidy. We focused on the Types section of the entry, examining how, of the autosomal chromosomes, only Trisomy 21 will result in a viable fetus most of the time. Students learned that when trisomy occurs in most of the other autosomal chromosomes, the result is an embryo that is non-viable, often resulting in miscarriage.
Back to the Case Study! To learn how Trisomy 21 occurs, students watched a short video illustrating non-disjunction. To put a human face on Trisomy 21, or Down Syndrome, students watched another short video about two young twins with Down Sydrome. Both videos are shown below:
The second video naturally leads to questions about twins, so slide 5 explains the difference between identical and fraternal (non-identical) twins. After slide 5, students received an article to read and annotate with questions about the connection between Down Syndrome and Alzheimer’s Disease.