What are the ways to determine the credibility of online information?

In what ways does DNA not fully determine our biology?

• It's a common truism that our DNA defines our (eukaryotes) biology (let's ignore environmental effects).  To what extent is this not true? For example, our DNA contains no information about our mitochondria which are inherited from our mothers and passed cell to cell (but perhaps this is considered part of human DNA).  Are there other interesting examples of information about our biology that exists outside of our DNA? For example, are there structural characteristics of a cell that are passed only because the original cell that divided had them?

• Answer:

  Mitochondrial DNA is, in fact, "our DNA," as it is copied and passed on when the cell replicates, though is not part of our nuclear genomic DNA. Other information that is not included in the the genetic code: the list of A's, T's, C's, and G's in our genomic DNA, is stored as epigenetics.  In fact, the definition of http://en.wikipedia.org/wiki/Epigenetics is "heritable changes in gene expression or cellular phenotype, caused by mechanisms other than changes in the underlying DNA sequence." Epigenetics covers heritable information like DNA http://en.wikipedia.org/wiki/Methylation#Epigenetics of cytosine (Part A of Figure), and http://en.wikipedia.org/wiki/Histone_modification#Functions_of_histone_modifications Modifications (Parts B and C of Figure), both of which affect gene expression. Figure from: http://www.sciencemag.org/content/330/6004/612 Some places to start learning about epigenetics: : Quora http://www.nature.com/nature/supplements/insights/epigenetics/index.html#reviews http://www.sciencemag.org/content/330/6004/611.short: Science