Most of us have been exposed to Mendelian genetics at multiple times in our scientific careers. However, like anything that you don’t use on a daily basis, it doesn’t hurt to have a quick refresher before proceeding into more difficult topics in genetics. This series of three videos provide a quick introduction to Mendelian genetics and focus on how to determine simple genotypic and phenotypic ratios for the monohybrid and dihybrid crosses.
Understanding the Punnett Square
The Punnett square is often used to visualize the phenotypic and genotypic ratios of simple Mendelian crosses. In this quick video, we present how to set up and interpret a Punnett square for a single-trait cross.
YouTube Link: http://youtu.be/wAPpKtwOayk
Understanding a Single-Trait (Monohybrid) Cross
The second video explore a one-trait Mendelian cross. In this example we are using the flower color of pea plants, since these traits are what are most often used in classes to describe a one trait cross. In this example we are using parents that are heterozygous for the trait, and therefore this is also an example of a monohybrid cross.
YouTube Link: http://youtu.be/rKE-HX3v50g
Understanding the Dihybrid Cross
Finally, we proceed to the more difficult of topics – the dihybrid or two-trait cross. In this video we keep it simple by using two heterozygous pea plants to demonstrate the generation of the common 9:3:3:1 ratio.
YouTubeLink: http://youtu.be/1QU2phs-hws
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