What is Epigenetics?
As an organism grows and develops, carefully orchestrated chemical reactions activate and deactivate parts of the genome at strategic times and in specific locations. Epigenetics is the study of these chemical reactions and the factors that influence them.
The Epigenome Learns From Its Experiences
Epigenetic tags act as a kind of cellular memory. A cell's epigenetic profile -- a collection of tags (Think of it as permanent post-it notes!) that tell genes whether to be on or off -- is the sum of the signals it has received during its lifetime.
The Changing Epigenome Informs Gene Expression
As a fertilized egg develops into a baby, dozens of signals received over days, weeks, and months cause incremental changes in gene expression patterns. Epigenetic tags record the cell's experiences on the DNA, helping to stabilize gene expression. Each signal shuts down some genes and activates others as it nudges a cell toward its final fate. Different experiences cause the epigenetic profiles of each cell type to grow increasingly different over time. In the end, hundreds of cell types form, each with a distinct identity and a specialized function.
Even in differentiated cells, signals fine-tune cell functions through changes in gene expression. A flexible epigenome allows us to adjust to changes in the world around us, and to learn from our experiences.
Cells Listen for Signals
The epigenome changes in response to signals. Signals come from inside the cell, from neighboring cells, or from the outside world (environment).
Early in development, most signals come from within cells or from neighboring cells. Mom's nutrition is also important at this stage. The food she brings into her body forms the building blocks for shaping the growing fetus and its developing epigenome. Other types of signals, such as stress hormones, can also travel from mom to fetus.
After birth and as life continues, a wider variety of environmental factors start to play a role in shaping the epigenome. Social interactions, physical activity, diet and other inputs generate signals that travel from cell to cell throughout the body. As in early development, signals from within the body continue to be important for many processes, including physical growth and learning. Hormonal signals trigger big changes at puberty.
Even into old age, cells continue to listen for signals. Environmental signals trigger changes in the epigenome, allowing cells to respond dynamically to the outside world. Internal signals direct activities that are necessary for body maintenance, such as replenishing blood cells and skin, and repairing damaged tissues and organs. During these processes, just like during embryonic development, the cell's experiences are transferred to the epigenome, where they shut down and activate specific sets of genes.
Breeder's note: We have been adamant regarding the importance of proper diet, a home environment, and lots of hugs for our Cavalier King Charles, understanding that genetic expression can be turned off or on, depending on personal experiences. It's entirely possible to have a healthy Cavalier with a wonderful background wind up exhibiting genetic health problems as a result of improper care.
This fascinating information is compliments of the University of Utah, Health Sciences. For more information, click on the link below: