Which statement explains why the recombination frequency between two genes is always less than 50%?

• A. Because independent assortment only occurs in prokaryotes, not eukaryotes.
• B. Because genes that are on the same chromosome and close together are less likely to be separated by crossing over, limiting the maximum recombination frequency to less than 50%.
• C. Because recombination frequency is determined solely by the number of chromosomes, not gene location.
• D. Because recombination events always occur between every pair of genes during meiosis.

Answer: (B)

Verified step by step guidance

1. Understand that recombination frequency measures how often two genes are separated by crossing over during meiosis, which reflects their physical distance on a chromosome.
2. Recall that genes located on the same chromosome are said to be linked, and the closer they are, the less likely a crossover event will occur between them.
3. Recognize that a recombination frequency of 50% corresponds to genes assorting independently, which happens when genes are either on different chromosomes or far apart on the same chromosome.
4. Note that recombination frequency cannot exceed 50% because beyond this point, genes behave as if they are unlinked due to multiple crossover events canceling each other out.
5. Conclude that the maximum recombination frequency is less than 50% for genes that are physically close on the same chromosome, explaining why recombination frequency is always less than 50% for linked genes.