Which of the following statements are true?
A. When two or more genes co-exist on the same chromosome, they may violate the principle of independent assortment during meiosis.
B. Positive interference occurs when the presence of one chiasma increases the possibility of another chiasma occurring in the immediate vicinity.
C. The proportion of crossovers never exceeds 50%.
D. The Chi-square test can be used for segregation ratios and detection of linkage.
Choose the most appropriate answer from the options given below: