Question

In studying a large number of families with a small deletion in a specific chromosome region, it is noted that the disease phenotype is distinctly different when the deletion is inherited from the mother as opposed to the father. What is the most likely explanation?

A. Imprinting
B. Mitochondrial inheritance
C. Sex-dependent penetrance
D. X-linked dominant inheritance
E. X-linked recessive inheritance

Answer 1

The most likely explanation for the distinct difference in disease phenotype when a small deletion in a specific chromosome region is inherited from the mother as opposed to the father is imprinting.

Step-by-step explanation:

The most likely explanation for the distinct difference in disease phenotype when a small deletion in a specific chromosome region is inherited from the mother as opposed to the father is imprinting.

Imprinting is an epigenetic phenomenon that results in differential expression of genes depending on whether they are inherited from the mother or the father. It occurs due to DNA methylation, histone modifications, and other factors that can influence gene expression.

In the case of the small deletion, certain genes in the deleted region may be imprinted differently depending on whether they were inherited from the mother or the father, leading to different disease phenotypes.