Do dahlias revert?

Hoping some of you smarties can provide some info. A friend planted a number a dahlias, different colors in the past years. She said they all reverted to pink this year. Can this really happen? If it does........how? Is there anything one can do to prevent it? Any advice would be greatly appreciated.

There can be wide variation at the end of the season when light is short, reds fade to pale orange, bright oranges fade to pale orange or yellow etc. But genetics also come into play and can give wide variation to the color of flowers. Blackberry Ripple is one that can be mostly white with purple flecks, half purple, half flecked, nearly all purple all in one season. Hollyhill Jester is another where there genes have their way and each bloom can be different.
http://hollyhilldahlias.aroundbeantown.com/NewIntros/Jester.html

That doesn't explain your friend's all turning pink but I would blame it on genetics or squirrels moving her pink tubers around when she wasn't looking..

I got a little more info from friend, Pooch. None of her dahlias were pink to begin with. She carefully diggs and labels them at season's end. These are dahlias she has had for several years and tends them carefully. The purples and reds changed, the white and yellows came true to color. She is aware of the same thing thing happening to another friend in Iowa. We think whatever happened, happened to them last season as this is the way they bloomed all summer. It is a blah shade of pink that they changed to.......a color she hadn't had before. We were wondering about a virus or chemical exposure as we are in farm country. So far no evidence to back up these suspicions

So I can't blame the squirrels....I still think it is a case of unstable genetics, but odd that it affected both her purples and reds. Maybe it was radiation? I hope not, for her sake.
http://www.springerlink.com/content/g8568503nh722348/

Google Verne Grant and you can find waaaaaaaaaaaay too detailed analyses of plant genetics and color expression, including our favorite, the dahlia. There's another article a bit more reader friendly done for the ADS, I think. If I find it I'll post a link, or someone else can.

Wow! Who knew this would be so complicated! I'll check out Verne Grant. You're a good researcher! Thank you for your help.

Should have known: the article was by Wayne Holland of "HY" dahlia origination fame, now moved on to growing wine grapes, I've read. Hy Lobster is one of my all time favorite red dahlias.

Good luck with this article. I had the usually entirely red Riverdance show up pure yellow one year on one branch only, but was unable to save remnants of that branch for propagation. It was fun while it lasted though. Haven't had such color weirdness since on any plant, but perhaps something similar happened to turn your friend's dahlias pink.
http://davesgarden.com/community/forums/t/649055/

http://www.members.shaw.ca/hydahlia/mutation.html

We're having Indian Summer here in Mn. so busy getting stuff done and haven't been here much. I passed the link of to my friend, she said to thank you for your trouble. She found the info. helpful. Wish we could have a great big coffee party some day and just chat. Thanks a bunch!