If two genes are on the same chromosome and close together, what is likely about their inheritance?

If two genes are on the same chromosome and close together, what is likely about their inheritance?

• A. They are linked and show little recombination.
• B. They are always inherited together.
• C. They will never recombine.
• D. They will always segregate independently.

Answer: (A)

When two genes are close together on the same chromosome, they are linked and tend to be inherited as a unit. The reason is that recombination (crossing over) between those nearby loci is infrequent, so parental allele combinations are passed on together to offspring more often than not. Occasional crossing over can still occur, so recombinant, new allele combinations can appear, but at a low rate. That’s why this situation doesn’t fit the idea of independent assortment, and it doesn’t mean they are always inherited together or that they never recombine.

When two genes are close together on the same chromosome, they are linked and tend to be inherited as a unit. The reason is that recombination (crossing over) between those nearby loci is infrequent, so parental allele combinations are passed on together to offspring more often than not. Occasional crossing over can still occur, so recombinant, new allele combinations can appear, but at a low rate. That’s why this situation doesn’t fit the idea of independent assortment, and it doesn’t mean they are always inherited together or that they never recombine.