The yellow pea allele (Y) is dominant to the green pea allele (y). The round pea allele (R) is dominant to the wrinkled pea allele (r).

You obtain a Yellow and round pea, and a Yellow and wrinkled pea, grow them into plants and test cross them both. Their genotypes are:

Plant 1: YyRr

Plant 2: Yyrr

You decide to cross Plant 1 with Plant 2.

Without drawing a 4 x 4 punnet square, how might you answer the following questions?

1. What is the chance of a pea from this cross having the genotype YYrr?

2. What is the chance of the pea from this cross being yellow and round?

Hint: The inheritance of the alleles from the 'yellow' gene and the inheritance of alleles from the 'green' gene are independent events. 

Put your thoughts and calculations below.