“Hey bright eyes…come here often?”
(Melvin always was a sucker for a big-eyed vestigial dame!)
I created the cartoon above, years ago, while in my junior year– Genetics class– at Drury University. Hey, before you roll your eyes…I got 2 bonus points for doing that from an instructor that said he didn’t believe in bonus points. Anyway, I love Genetics. I wrote the curriculum for a semester class that hits the basics for Mendelian Genetics, and I thought I would share one of the lessons that has been successful with my At-Risk students.
Student prep for this lesson: They must have a working genetic vocabulary of: genotype, phenotype, dominant, recessive traits. They must also understand how to create a Punnett square with multiple traits.
Combinations and Possibilities
Directions: First: Write out the possible combination of traits for each of the following genotypes. Second: Then create a Punnett square for couple 1 and 2. Next create a Punnett square for couple 3 and 4. Identify the phenotypical combinations possible and using fractions the phenotypical possibilities for each couples offspring.
1.Man—BbTTCc 2. Woman–BbTtCC
3. Man–bbTTcc 4. Woman–BbttCC
5. Man—BbTtCc 6. Woman–BBTTCC
First Possible combinations– First 1-6
5. BTC–BtC–BTc–Btc 6. BTC
Punnett Square Keys:
#1 and #2 Cross Phenotypical possibilities and fractions for their offspring:
Brown eyes/Tall/Curly hair = 12/16 or 3/4
Blue eyes/Tall/Curly = 4/16 or 1/4
#3 and #4 Cross Phenotypical possibilities and fractions for their offspring:
Brown eyes/Tall/Curly = 1/2
Blue eyes/Tall/Curly = 1/2