Final answer:
Epigenetics is the study of heritable changes in gene expression that do not involve alterations to the DNA sequence itself. These changes can affect gene activity and are passed down during cell replication, influencing cellular differentiation and organism development.
Step-by-step explanation:
The term you are looking for is epigenetics. This field of biology looks at how different gene expressions can be transmitted during replication, with no changes in the actual DNA sequence. Unlike genetic changes that alter the sequence, epigenetic changes affect how genes are turned on or off. For example, the addition of methyl groups to the DNA backbone can silence genes, and modification of histone proteins can either condense or relax chromatin structure, affecting gene expression. Different cells in a multicellular organism have the same DNA but can become different cell types due to different patterns of gene expression. This differentiation is due to various epigenetic mechanisms that regulate gene expression at different levels, such as transcriptional, post-transcriptional, and translational stages.
These epigenetic changes are heritable, meaning that they can be passed from parent cells to daughter cells during mitosis. This is essential for the development and functioning of multicellular organisms, where various cell types must maintain distinct identities. Epigenetics is a vast field that plays a critical role in development, disease, and inheritance without altering the DNA sequence itself.