Teaching about Karyotypes and Chromosomes

My students have always been fascinated with karyotypes.  I usually teach about karyotypes right after  long unit on cellular respiration and photosynthesis, right before I get into mitosis and meiosis.  Students often have a lot of misconceptions about chromosomes and karyotypes.

Here are a few web resources and teaching ideas you can use when teaching about chromosomes and karyotypes! (All links work as of 12/10/2014)

Web Resources

Learn.Genetics from University of Utah has a great site with a lot of lesson ideas and activities.  Here is one students can use to create a karyotype by matching chromosome pairs on the screen.  This could really help students to understand that each chromosome normally appears in a pair, within a karyotype.  They are the same size and have the same banding patterns.

This site also has a lot of information about how karyotypes can be used to diagnose genetic disorders.  It goes into translocations and deletions and has a few animations worth checking out!

This animation from UCDavis is great because it shows how karyotype analysis is actually done.  It describes how the blood sample is collected and analyzed.

There are several videos on this site by Cold Spring Harbor Labs.  Here is one about chromosome maps.

Here are some actual karyotypes collected by ZooWeb and Wisconsin State Labs.  They are great for showing students what karyotypes actually look like before they are analyzed and what they look like after!

Here are 3 case studies from the University of Arizona with patient histories and karyotypes to analyze.

Lessons

Cell division is a topic I studied extensively during my researcher years and I have found that concepts like independent assortment of chromosomes are really difficult for students to understand without a very clear model or activity.  So I designed several activities to address big misconceptions students have about chromosomes and karyotypes.

This Color-Your-Own Karyotype Lesson really teaches students about karyotypes, inheritance of chromosomes, and independent assortment, all while they are happily coloring!  Students will color their grandparents' chromosomes, then their parents' chromosomes, and their own, creating a karyotype with 4 different colors symbolizing what chromosomes they inherited from each grandparent.  At the end, they will be able to understand that they can actually be more related to one grandparent than the other, which will blow their minds!  

Students often ask how chromosomal abnormalities happen.  How are they actually produced in cells during mitosis or meiosis?  Often textbooks and other resources stop at the explanation "It's a mistake during crossing-over!" and students still don't understand really why.  In this resource, I show students in a step-by-step manner how to draw crossover products.  After they understand how to draw crossover products (using colored pencils!) they can then understand how to draw crossover products when crossing over goes wrong.  This activity really is geared toward upper level students (lower level students may really struggle with this activity).

When I was teaching, I was always looking for great quality karyotype pictures to put on my quizzes and tests.  Students like to play detective and look at a karyotype and tell me what the genetic disorder is.  It's also nice to have great pictures for powerpoints, posters, etc.  But it is really hard to find non-grainy pictures on the web.  So I created a clip art set with karyotypes for each major chromosomal disorder.  

I hope you found these helpful!  I have decided to keep writing topical blog posts featuring web resources and lessons that teachers can really use.  What topic in biology are you struggling to find lesson ideas for?  Leave me a comment below and it might be my next blog post inspiration!