Maximum recombination frequency between two genes during meiosis of a diploid organism can be 50%.

Explanation of Options

• (1) 25%: This value is too low and does not represent the maximum limit of recombination frequency. It could be an intermediate frequency between two linked genes but not a maximum.

• (2) 50%: This is the correct maximum recombination frequency. When genes assort independently or are very far apart on the same chromosome, the recombination frequency reaches 50%. This means half of the gametes are recombinant and half are parental. It corresponds to independent assortment either due to genes being on different chromosomes or being very far apart on the same chromosome.

• (3) 75%: Recombination frequency cannot exceed 50%, so 75% is not possible biologically. Frequencies above 50% indicate independent assortment, but are not measured as more than 50%.

• (4) 100%: This is impossible in meiosis. The maximum is capped at 50% because crossing over events during meiosis result in a maximum of 50% recombinant gametes due to the mechanics of chromosome segregation.

Introduction:
Recombination frequency is a fundamental genetic concept that measures the likelihood of crossover events separating two genes during meiosis. For diploid organisms, the maximum recombination frequency achievable between two genes is crucial for understanding gene linkage and inheritance patterns. This article explains why this maximum is 50%, clarifying common misconceptions and illustrating the implications for genetic mapping.

This maximum 50% recombination frequency arises because during meiosis, crossover events between homologous chromosomes can produce recombinant and non-recombinant chromatids. Due to the random resolution of crossover points, only about half of the gametes are recombinant, capping the frequency at 50%. Frequencies less than 50% suggest linkage and physical proximity on the same chromosome, while 50% indicates independent assortment or very distant genes on the same chromosome.

Thus, the maximum recombination frequency between two genes in meiosis is 50% (Option 2).​