What is the focus of epigenetics?

• A. The physical structure of DNA
• B. Changes in gene expression not caused by DNA sequence changes
• C. The evolution of species
• D. Gene therapy techniques

Answer: (B)

The focus of epigenetics is centered on changes in gene expression that do not involve alterations to the underlying DNA sequence. This involves mechanisms such as DNA methylation and histone modification, which can influence how genes are turned on or off. These modifications can be heritable and affect an organism's phenotype without changing the genetic code itself. The significance of epigenetics lies in its ability to explain how environmental factors and life experiences can influence gene expression, leading to diverse biological outcomes and potentially heritable traits.

In contrast, while the physical structure of DNA is a foundational aspect of molecular genetics, it does not address the regulatory mechanisms that are central to epigenetics. The evolution of species pertains more to the broader field of evolutionary biology and is not a specific focus of epigenetics itself. Gene therapy techniques aim to address genetic disorders by altering the sequence of DNA directly or introducing new genes, which is distinct from the epigenetic focus on gene regulation without changing the DNA sequence.