Let's solve the problem by determining the phenotypic ratio of the offspring when two parents heterozygous for both traits (unattached earlobes and cleft chin) are crossed.
1. Determine parent genotypes:
Each parent has the genotype EeAa since they are heterozygous for both traits.
2. Determine possible gametes:
Each parent can produce four types of gametes: EA, Ea, eA, ea.
3. Construct a Punnett Square:
We create a Punnett square to find the offspring genotypes and their corresponding phenotypes. The Punnett square will have the gametes from one parent along the top and those from the other parent along the side.
[tex]\[
\begin{array}{|c|c|c|c|c|}
\hline
& EA & Ea & eA & ea \\
\hline
EA & EEAA & EEAa & EeAA & EeAa \\
\hline
Ea & EEAa & EEaa & EeAa & Eeaa \\
\hline
eA & EeAA & EeAa & eeAA & eeAa \\
\hline
ea & EeAa & Eeaa & eeAa & eeaa \\
\hline
\end{array}
\][/tex]
4. Phenotypic Ratios:
- Unattached earlobes and cleft chin (E_A_):
- EEAA, EEAa, EeAA, EeAa
- Total: 9
- Unattached earlobes and no cleft (E_aa):
- EEaa, Eeaa
- Total: 3
- Attached earlobes and cleft chin (eeA_):
- eeAA, eeAa
- Total: 3
- Attached earlobes and no cleft (eeaa):
- eeaa
- Total: 1
Therefore, the phenotypic ratio of the offspring is:
[tex]\[
\boxed{9}: \boxed{3}: \boxed{3}: \boxed{1}
\][/tex]
