Which factor has the greatest influence on the expression of a genetic disorder such as Prader-Willi syndrome or Angelman syndrome through the process of genomic imprinting?
A)Paternal age at time of conception
B)Maternal age at time of conception
C)The gender of the parent transmitting the deletion
D)The number of bases deleted from the chromosome

Question

Quizplus · Accepted Answer

The same deletion of 15q can result in either Angelman syndrome or Prader-Willi syndrome, depending on which parent contributed the chromosomal deletion. When no maternal material from 15q(11-13) is present, and only paternal material is expressed, Angelman syndrome results. When no paternal material from 15q(11-13) is present, and only maternal material is expressed, Prader-Willi syndrome results. Genomic imprinting is an epigenetic event that results in a qualitative difference in expression based on parental gender. The effect of an imprinted gene allele from one parent means that only the nonimprinted allele from the other parent is expressed, which is a problem if the allele is abnormal. The age of the parent and the size of the deletion are not critical factors in the expression of this genetic disorder.

Which Factor Has the Greatest Influence on the Expression of a Genetic