Final answer:
The fraction of offspring with the genotype aabbcc from the cross of aabbcc and AaBbCc is 1/8, calculated using the probability method assuming independent assortment.
Step-by-step explanation:
To calculate the fraction of offspring that would have the genotype aabbcc after crossing an individual with the genotype aabbcc with one that is heterozygous for all three genes (AaBbCc), we use the probability method for each gene.
Since the first parent can only pass on the recessive alleles (a, b, c), and the heterozygous parent has a 1/2 chance of passing on the recessive allele for each gene, the probability for each gene to be homozygous recessive in the offspring (aa, bb, cc) is (1/2) × (1/2).
Multiplying these probabilities together for all three genes gives us (1/2)³, which equals 1/8.
Therefore, the fraction of offspring with the genotype aabbcc from this cross is 1/8.
This calculation assumes that there is no gene linkage and the genes are sorting independently following Mendel's laws.