Answer:
all of the above
Step-by-step explanation:
Epigenetic alterations are modifications of the genome transmitted during cell division, which do not involve changes in the DNA sequence, are hereditary and are capable of modifying gene expression. In addition, they are temporary modifications that allow DNA to be transcribed and have the ability to move histones to open or close a chromosomal region. There are three main mechanisms of epigenetic alterations: DNA methylation, histone modifications and genomic imprinting.