Epigenetics in evolution:
I didn’t mean to make a double entendre, but I guess it’s there.  Surely ideas about epigentics are changing.  But what I really mean is to refer to a an article (Elisabeth Pennisi Evolution Heresy? Epigenetics Underlies Heritable Plant Traits SCIENCE vol. 341 no. 6150 September 6, 2012 page 1055 reviewing a presentation by Frank Johannes of the University of Groningen in the Netherlands at the XIV Congress of the European Society for Evolutionary Biology held August 19-24, 2013 in Lisbon) that tells us that methylation patterns can affect things like flowering time and root length in the plant Arabidopsis.   Crucially these methylation patterns can persist over eight generations. 

For me the surprise is that there should be any doubt.  Epigenetic markers can persist over generations, epigenetic markers can effect gene function and if you have inheritable variation you are going to get selection.  However there does seem to be a lot of resistance.

One of the catches is that methylation seems to be changed by environmental influences.  Somehow the notion changes acquired because of the environment lead to inherited changes that adapt to the environment irritates folks.

For me the exciting number is that eight generations.  If you recall it takes about five or ten generations for infertility from insufficient consanguinity to work its way through a population.  And I have said before that this has to be epigenetic in nature; it’s too fast for DNA mutations.  The question is whether it is too fast to affect fertility generations down the road; at current reading the answer must be no; it’s just right. 

It seems to me that there could be a sort of scratch pad effect here.  Epigenetic markers do change rather quickly.  If a new environmental niche shows up, some new DNA mutation, maybe something that resurrects a deactivated gene, might offer a chance for the species to adapt.  But just suppose an epigenetic pattern arises that does the same thing.  The species can then go on exploiting the new niche, hanging on by the skin of its teeth so to speak, until the proper DNA change comes along and secures the advantage.  It’s just a thought.

There have been 63 visitors over the past month.

Home page