In the region of chromosome 15 that is deleted in both Prader-Willi and Angelman syndrome, there are a number of different genes, some encoding proteins and others non-coding, meaning that they produce RNA but not protein. There is also an imprinting center, which affects expression of several nearby genes. This imprinting center is maternally imprinted. Which of the following statements are true? (select two answers) a. The DNA in the imprinting center is methylated during sperm development and escapes reset during early development.
b. The DNA in the imprinting center is methylated during egg development and escapes reset during early development.
c. The imprinting center has DNA methylation on the maternal chromosome.
d. The imprinting center has DNA methylation on the paternal chromosome.