Question

The distance between two genes in a chromosome is measured in cross-over units, what does it represent?

• A. Ratio of crossing over between them
• B. Percentage of crossing over between them
• C. Number of crossing over between them
• D. None of the above

Answer 1

Answer: (B)

Percentage of crossing over between them

Recombination can occur between any two genes on a chromosome, the amount of crossing over is a function of how close the genes are to each other on the chromosome. If two genes are far apart, for example at opposite ends of the chromosome, crossover and non-crossover events will occur in equal frequency. Genes that are closer together undergo fewer crossing over events.