Final answer:
The proportion of offspring with the genotype aabbccdd from the cross AaBbCcDd × AabbCCdd, assuming independent assortment, is 1/64.
Step-by-step explanation:
The student's question is asking about the proportion of offspring with the aabbccdd genotype resulting from a cross between the genotypes AaBbCcDd and AabbCCdd assuming independent assortment. To determine the answer, we need to consider the probability of obtaining the recessive allele from each parent for each gene.
For the gene A, the first parent (Aa) has a 50% chance (1/2) of passing the 'a' allele, while the second parent (Aa) has a 100% chance (1) as they only carry the 'a' allele. For the gene B, the first parent (Bb) has a 50% chance (1/2) of passing the 'b' allele, and the second parent (bb) also has a 100% (1) chance. For gene C, the probability is 50% (1/2) from the first parent (Cc) and 100% (1) from the second parent (CC) who only has 'c' alleles. Lastly, for gene D, both parents have a 50% chance (1/2) of passing on the 'd' allele.
Using the product rule, we can calculate the probability: 1/2 (for A) × 1/2 (for B) × 1/2 (for C) × 1/2 × 1/2 (for D) = 1/16. Therefore, the correct answer is 1/16 or option C) 1/64.