From Ann Gauger at Evolution News & Views
About forty years ago, a biochemistry professor told my class that now that the genetic code had been worked out and the lac operon discovered, the only thing left for us students was to work out the details. Boy, was he wrong!
If there’s one thing I’ve learned over the last forty years, it is that every ten years or so the biological apple cart is upset, and a long-established “fact,” an assumption based on incomplete knowledge, is proven to be wrong.
I am sure you can find textbooks that still include some of these old “facts.” Below is a partial list of those assumptions that have had to be revised, and some that are still under discussion.
1. Old fact: DNA is stable and genes don’t hop around.
New discovery: Mobile genetic elements can hop from place to place in the DNA, duplicating themselves and changing gene expression. Sometimes they carry surrounding genes with them. More.