To complete the Punnett Square for the genotypes you've provided (AA, Aa, Aa, aa), let's set it up:
A A
-----------------
A | AA AA |
-----------------
a | Aa Aa |
-----------------
a | aa aa |
The completed Punnett Square shows the following genotypes:
- 2 AA
- 2 Aa
- 1 aa
Now let's list the genotypes again to interpret their phenotypes assuming that "A" (dominant) expresses a dominant trait and "a" (recessive) expresses a recessive trait:
- AA → dominant phenotype
- Aa → dominant phenotype
- aa → recessive phenotype
From the completed Punnett Square:
- Dominant phenotypes (AA + Aa): 4
- Recessive phenotypes (aa): 1
Therefore, the phenotypic ratio is:
- Dominant:Recessive = 4:1
So, the answer to the second question is:
4:1