Which of the following is not a type of epigenetic modification?

• A. RNA splicing
• B. Histone methylation
• C. DNA methylation
• D. Histone acetylation

Answer: (A)

Verified step by step guidance

1. Understand the concept of epigenetic modifications: Epigenetic modifications are changes to the genome that do not involve alterations in the DNA sequence itself but can affect gene expression. These modifications can be inherited and are reversible.
2. Identify common types of epigenetic modifications: The most well-known types include DNA methylation, histone methylation, and histone acetylation. These modifications can influence how tightly DNA is wound around histones, thereby regulating gene expression.
3. Define DNA methylation: This involves the addition of a methyl group to the DNA molecule, typically at cytosine bases, which can suppress gene expression.
4. Define histone modifications: Histone methylation and acetylation are processes where methyl or acetyl groups are added to histone proteins, affecting how tightly DNA is wrapped around these proteins and thus influencing gene expression.
5. Recognize that RNA splicing is not an epigenetic modification: RNA splicing is a process that occurs after transcription, where introns are removed, and exons are joined together to form mature messenger RNA (mRNA). It does not involve changes to the DNA or histone proteins and is not considered an epigenetic modification.