# Question #99310

Dec 9, 2017

See below...

#### Explanation:

1) You basically just draw a single square since a square is technically a one by one.

2) (I’m assuming that the dominant trait is taster/roller) Since it’s homozygous, we put that as both uppercase letters to show it’s a dominant trait. And since (I’m assuming) that nontasters and nonrollers are recessive, we put those both as lower case.

3)
Genotypes (genetic construction of the child) $\to$ TtRr
Phenotypes (observable characteristic) $\to$ Taster/Roller (since they have a dominant allele in the code- since they have an uppercase in the code for both Taster and Roller)

4) Draw a 4 by 4 grid. So 4 rows and 4 column space.

5) Heterozygous means different allele for the dominant traits, so you would want to cross TtRr x TtRr. It should look something like this in the end. (Excuse my bad handwriting)

6) Count the specified traits in the boxes:
Roller/Taster (Need at least one R, and one T) = 9/16 = 56.25%
Roller/non-taster (Need at least one R, and both lowercase t) = 3/16 = 18.75%
Non-roller/Taster (Need both lowercase r and at least one T) = 3/16 = 18.75%
Non-roller/Non-taster (Need both lowercase r and both lowercase t) = 1/16 = 6.25%