A child is diagnosed with cystic fibrosis. History reveals that the child's parents are siblings. ...

ANS: C
Consanguinity refers to the mating of two related individuals, and the offspring of such matings are said to be inbred. Consanguineous matings produce a significant increase in recessive disor-ders and are seen most often in pedigrees for rare recessive disorders. X-inactivation occurs when one X chromosome in the somatic cells of females is permanently inactivated. Genomic imprint-ing is related to methylation and other changes. Obligate carriers are those who have an affected parent and affected children and, therefore, must themselves carry the mutation.