Maximum recombination frequency between two loci is
Recombination frequency measured as percentage recombinant progeny increases with physical distance between loci because greater separation provides larger opportunity for crossover. Maximum theoretical frequency for loci on different chromosomes or far apart on same chromosome is one half, corresponding to independent assortment where 50 percent gametes recombinant and 50 percent parental. At this limit loci behave as unlinked, obeying Mendel's second law. Frequency plateau at 0.5 defines unlinked status important for constructing linkage maps and calculating genetic distances in centiMorgans. This principle illustrates essential molecular mechanisms governing replication fidelity and mutation fixation relevant for exam interpretation.
Ref: Lodish et al., Molecular Cell Biology, 9th ed., Chapter 9: Maximum Recombination Frequency 0.5 Explanation