Sure, let's break down the problem and determine the ratios of offspring with different combinations of traits from the given genetic cross: parents both heterozygous for unattached earlobes (Ee) and cleft chin (Cc).
Parents' Genotypes:
- Both parents are heterozygous for both traits: EeCc.
Traits Information:
- Unattached earlobes (E) are dominant to attached earlobes (e).
- Cleft chin (C) is dominant to no cleft (c).
Possible Offspring Genotypes:
To find the possible genotypes of the offspring, we need to consider the combinations of the alleles from both parents. We'll use a Punnett Square to establish all genotype possibilities for the offspring. We can then tally the phenotype ratios based on our genotype results. However, based on the established possible genotypes, we already have the outcomes:
1. Unattached earlobes and cleft chin (E_C_):
- This corresponds to combinations having at least one E and one C (EEC_, EeC_).
- There are 9 such combinations.
2. Unattached earlobes and no cleft (E_cc):
- This corresponds to combinations having at least one E and two c's (EEcc, Eecc).
- There are 3 such combinations.
3. Attached earlobes and cleft chin (eeC_):
- This corresponds to combinations having two e's and at least one C (eeC_).
- There are 3 such combinations.
4. Attached earlobes and no cleft (eecc):
- This corresponds to combinations having two e's and two c's (eecc).
- There is 1 such combination.
Total Number of Offspring:
- By adding up all the combinations, we get a total of 16 possible offspring.
Ratios:
- Unattached earlobes and cleft chin (E_C_): 9 out of 16
- Unattached earlobes and no cleft (E_cc): 3 out of 16
- Attached earlobes and cleft chin (eeC_): 3 out of 16
- Attached earlobes and no cleft (eecc): 1 out of 16
Hence, the ratio of offspring with the given traits are:
- Unattached earlobes and cleft chin: 9 / 16
- Unattached earlobes and no cleft: 3 / 16
- Attached earlobes and cleft chin: 3 / 16
- Attached earlobes and no cleft: 1 / 16
