Final answer:
Epigenetic inheritance refers to changes in gene expression that do not alter the DNA sequence but occur due to chemical modifications like DNA methylation and histone modification. These heritable changes can contribute to the differentiation and variety of cells and tissues within organisms and are influenced by environmental factors.
Step-by-step explanation:
The modification that occurs to a nuclear gene that alters gene expression without modifying the DNA sequence is called epigenetic inheritance. This type of inheritance involves changes in gene expression that are not caused by alterations in the DNA sequence but through chemical modifications such as DNA methylation and histone modification. These epigenetic changes can affect how genes are turned on or off and are indeed heritable, meaning they can be passed down through generations of cells during mitosis, contributing to the diversity of tissues and organs within an organism.
Epigenetics is a rapidly growing field in biology that explores how environmental factors can lead to heritable changes in gene expression that do not involve changes to the underlying DNA sequence. For example, environmental factors like diet, stress, and exposure to toxins can bring about epigenetic alterations that may influence an individual's health and can be transmitted to their offspring. This advances our understanding of inheritance beyond the classical genetic perspective and opens up new possibilities in the field of genetics research.