easy tips for teaching pedigrees
Time to teach pedigrees! After all you've taught the kids about inheritance, this should be a piece of cake! Give them a chart, look at the colored in squares or circles, and determine the inheritance pattern. Easy, right?!
Well, it can be... but it depends how you do it. When it comes to pedigrees, it's only as hard (or easy) as you make it. My mantra when it comes to teaching pedigrees is this: these kids, statistically speaking, are not going to become genetic disease counselors any time soon. However, pedigrees can be a GREAT tool for critical thinking and showing understanding. Making them TOO easy, means you might miss out on the critical thinking component, but making them TOO hard just leads to mental blocks and frustration.
Here are 3 4 easy tips for teaching pedigrees in your classroom:
1. Pedigrees are useless if your students can't decipher the chart. It's all hieroglyphics to them at first. Don't rush through the Roman numerals, the numbers, and the shapes. Make sure your kids know how to find, for example "individual I-5", and that they can tell you individual I-5's relationship to individual III-7, before moving on to the inheritance patterns.
2. You don't need to necessarily introduce carriers right away. Sometimes, the more shapes and shades that are coming at them at once will lead to more confusion down the road. I start with the easiest: dominant vs recessive autosomal pedigrees. Once kids have a solid grasp on this, we then work together to find any heterozygous individuals in an autosomal recessive pedigree and expand on it from there.
3. Pedigrees are a great tool for students to navigate critical thinking skills. If the pedigrees are too complicated, this can prohibit some productive thought flow, and lead to frustration. I’d recommend keeping pedigrees simple, and you can add more difficult ones as you go, or as bonus work. For example, if YOU have trouble deciphering between autosomal recessive and X linked recessive on a pedigree, your students probably will, too. Trash it and use a simpler pedigree. Which brings me to number 4...
4. X linked recessive and autosomal recessive can be VERY similar. To help students navigate this, you could give them the pattern of inheritance, and have them explain WHY it’s this pattern. This is a more effective way of testing their understanding.
Pedigrees, though they seem simple, can sometimes be deceiving! To help with this, I've created a Pedigree Cheat Sheet that students can use as they navigate pedigrees. Download it below: