Question

What map unit (Centimorgan) is adopted in the construction of genetic maps?

• A. A unit of distance between genes on chromosomes, representing 50% crossover.
• B. A unit of distance between two expressed genes representing 10% crossover.
• C. A unit of distance between two expressed genes representing 100% crossover.
• D. A unit of distance between genes on chromosomes, representing 1% crossover.

Answer 1

The correct option is D

A unit of distance between genes on chromosomes, representing 1% crossover.

Correct option: D

Explanation of correct option:

• One map unit or Centimorgan is the distance between two genes on the same chromosome, which shows a 1% crossover or recombination frequency.
• Genes that are in close proximity or tightly linked show very low recombination.

Explanation of incorrect option:

Option A:

One map unit or Centimorgan is the distance between two genes on the same chromosome, which does not show a 50% crossover or recombination frequency.

Option B:

One map unit or Centimorgan is the distance between two genes on the same chromosome, which does not show a 10% crossover or recombination frequency.

Option C:

One map unit or Centimorgan is the distance between two genes on the same chromosome, which does not show a 100% crossover or recombination frequency.

Final answer: A unit of distance between genes on chromosomes, representing 1% crossover.