Final answer:
A forked-line diagram is used to calculate the F2 offspring probabilities in a trihybrid cross. It represents a diagrammatic version of the product rule, leading to a phenotypic ratio of 27:9:9:9:3:3:3:1 when each gene assorts independently.
Step-by-step explanation:
The technique for predicting the outcome of a genetic cross is a fundamental concept in Biology, particularly in genetics. When dealing with a three-point cross involving F2 offspring probabilities derived from F1 heterozygote parents (AABBCC and aabbcc), it is necessary to understand the probability of the genotypes of the next generation. One such tool is the forked-line diagram, which is a visual representation of the product rule in genetics to predict the outcome of trihybrid crosses (crosses involving three traits).
For example, in order to calculate the outcome of a trihybrid cross, you would set up the forked-line diagram for each trait, segregate the alleles, and then multiply the probabilities along each forked path. When each gene assorts independently, the phenotypic ratio for a trihybrid F2 generation (from the cross of the F1 generation) would be 27:9:9:9:3:3:3:1, indicating the predicted distribution of various trait combinations. This process helps in understanding the complex interactions and distribution of traits through the offspring.