Final answer:
Analyzing double crossover events is the most convenient method for determining gene order from three-point cross results, as it provides insight into the arrangement of genes on a chromosome.
Step-by-step explanation:
The most convenient method for determining gene order from three-point cross results is by the analysis of double crossover events (Option D). In a three-point cross, individuals with a known genotype are crossed, and their offspring are analyzed for recombination. It involves looking at the frequency of offspring phenotypes to deduce the arrangement of genes on a chromosome. Double crossovers occur least frequently and reveal the gene in the middle, providing crucial information on gene order. This type of analysis is different from methods such as PCR, which is used to amplify DNA, and does not directly provide information on gene order. Other methods mentioned, such as comparison of DNA sequences (Option B) or application of the chi-square test (Option C), are also used in different contexts of genetic analysis but for a three-point cross specifically, double crossover analysis is most pertinent.