You're probably familiar with the phrase, "You are what you eat." But did you know that you are also what your mother and grandmother ate? The budding science of epigenetics shows that our physical makeup is about much more than inheriting our mother's eyes or our father's smile.
We are accustomed to thinking that the only thing we inherit from our parents are genes -- packets of information in DNA that give instructions for proteins. These genes determine our physical traits such as hair and eye color, height, and even susceptibility to disease.
But we also inherit specific "modifications" of our DNA in the form of chemical tags. These influence how the genes express our physical traits. The chemical tags are referred to as "epigenetic" markers because they exist outside of (epi-) the actual sequence of DNA (-genetics).
Let me use an analogy to explain. The following sentence can have two very different meanings, depending on the punctuation used. "A woman, without her man, is nothing" or "A woman: Without her, man is nothing." Perhaps it's a silly illustration, but it gets the point across.
The words of both sentences are the same, but the meaning is different because of the punctuation. The same is true for DNA and its chemical tags. The sequence of DNA can be identical but produce different results based on the presence or absence of epigenetic markers. For example, identical twins have the same DNA sequence but can have different chemical tags leading one to be susceptible to certain diseases but not the other.
[Read the rest of the article at Answers in Genesis.]