Snpedia also provides additional information about the SNP associated with the trait. Students can compare both variants to show how tasters have a sequence that allows them to build the receptor protein that binds to PTC. For example, for tasters and non-tasters:
![the anchoring phenomenon the anchoring phenomenon](https://www.nsta.org/sites/default/files/blog/2017/06/anchoring-q-and-pic-4.jpg)
Throughout the lecture and activities, we continually refer to the original phenomenon, showing how SNPs (single nucleotide polymorphisms) can be used to establish variations in phenotypes. I usually present this topic after Mendelian genetics, so they do understand recessive traits and inheritance patterns. The lesson starts with the anchor question/phenomenon: “How do small changes in DNA lead to big changes in traits?” I try to make something simple for freshman that was also tangible, like the ability to taste. For a more nuanced explanation of the gene, check out “ Myths of Genetics.” Lesson Structure and Activities Environmental factors may also influence the ability to taste PTC. Homozygotes (AA) may report a very strong bitter taste and heterozygotes may not have as strong of a response. The ability to taste PTC is a dominant trait so many members of the class will experience a bitter taste. It is sold as genetic taste strips by Amazon and biological supply companies. PTC, or phenylthiocarbamide, is a chemical that tastes bitter to some people but is tasteless to others. I start my lecture slides on DNA with an anchoring phenomenon on PTC and taste testing. When dealing with molecular biology, younger students tend to have trouble connecting the concepts to their own experiences.
![the anchoring phenomenon the anchoring phenomenon](https://www.yirmilerim.com/wp-content/uploads/2017/09/pexels-photo-357499.jpeg)
![the anchoring phenomenon the anchoring phenomenon](http://fqmom.com/wp-content/uploads/2016/10/Cover2-min.jpg)
When I plan lessons, I try to locate phenomena that can be observable and interesting. The NGSS suggests using anchoring phenomenon as ways to engage students in lessons. Natural phenomena are observable events that inspire questions and curiosity in students.