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Spring SAVY 2022 – Dabbling with DNA for 3rd/4th Grade (Schott)

Posted by on Monday, February 21, 2022 in blog.

The Dabbling with DNA class convened on Saturday February 19th to study heredity, genetics, and DNA.  We started the class with a discussion of variation in us and other species and thought about which traits are genetic (eye color) and which not so much (preference for pizza).  We quantified differences among us for eye color, hair color, and tongue rolling.  We generated bar charts for the different traits and calculated the frequency of each phenotype.  They filled in Punnett squares and saw the value in using them to calculate the probability of different outcomes.  We studied the structure of DNA, built a model out of clay, and figured out how information is embodied in the sequence of bases in DNA.  The last activity before lunch was transcription and translation.  We simulated the passing of information from DNA to RNA to proteins by rewriting a message and passing it to the next person.  After rewriting the message “apple sauce” six to seven times it had mutated to “apple cow” in one team.  We finished the morning with a look at the genetic code, practiced transcribing and translating a gene, and discussed the importance of doing this correctly.

The first afternoon activity was extracting DNA from strawberries.  This is a simple procedure in which they crush the berries in a Ziplock, add a soapy-salty extraction buffer, gently mix, run the mixture through a coffee filter, put the filtrate in a tube, and then carefully add rubbing alcohol.  They learned that the soap breaks up the cells, the salt separates the DNA from associated proteins, and the alcohol causes the DNA to precipitate.  It is a simple and safe procedure that allows them to see DNA.  Next, they built Crazy Creatures which demonstrates that when starting with identical heterozygous parents it is very unlikely to generate 13 offspring that have the same genotype/phenotypes for 14 traits.

It was a lot of information and provided a good introduction to heredity, genetics, and DNA.  I want to encourage them to keep learning.  A good resource for genetics information is the Cold Spring Harbor website (https://dnalc.cshl.edu/).  For both genetics and evolution I suggest the Howard Hughes Medical Institute’s BioInteractive website (https://www.biointeractive.org/).  I hope your child enjoyed the class as much as I enjoyed being their teacher!