Hmm, well, while your environment and such most certainly have an impact on your DNA and protein expression, it isn't exactly a "memory embedded in your DNA" situation.

In the case of the flat worm, it seems much more likely that as the worm was conditioned to respond negatively to light and then cut in half, three things were happning:

1) The worms neurons were sending input signals to the somatic cells, as normal.
2) The somatic cells were "learning" that this stimulus was shortly followed by a pain stimulus, and thus began learning to contract/expand immediately when exposed to the light.
3) When the worm is cut, the somatic cells in the lower half are still conditioned to respond to the stimuli. Their responses, just like the cell responses in your own body, act independent of other input from the brain. Thus, the absence of a brain does not affect their stimulus response.

So, basically, yes, the DNA does change (and by change I mean certain regions of the DNA compact or decompact to allow for gene regulation) in response to environment. When the worm is being conditioned, it is likely that the cells are producing more motor proteins and kinases capable of moving and bending the cells. This change, however, would not pass on to progeny, most likely. The reason you see it in the worm that has been cut is due to somatic cell condition, not germ cell conditioning.

Also, as for your own recollection of memories you feel are embedded in your DNA, I just really don't think that is possible. What you may feel is a memory may just be something you absorbed passively. Our brains are constantly receiving input, even in our sleep (both from dreams and things in the waking world). It is much more likely that you passively absorbed an event or piece of knowledge, rather than having had it passed to you through your genes.

Hope this helps!

Your friendly, neighborhood geneticist,
Matt

EDIT: Editted for stupid typos....

[edit on 9/5/2007 by VneZonyDostupa]

Originally posted by VneZonyDostupa
So, basically, yes, the DNA does change (and by change I mean certain regions of the DNA compact or decompact to allow for gene regulation) in response to environment. When the worm is being conditioned, it is likely that the cells are producing more motor proteins and kinases capable of moving and bending the cells. This change, however, would not pass on to progeny, most likely. The reason you see it in the worm that has been cut is due to somatic cell condition, not germ cell conditioning.

Makes sense, but that's just one example. What about newborn babies knowing how to swim? Or a chick knowing that a hawk is dangerous. Or a deer avoiding a wolf. Or animals avoiding lines where electric fences were previously set up (when it was the animal's parents, not themselves, who had ever experienced the danger of the electric fence). I can think of many other examples in nature without even researching.

Certain traits are clearly inherited, especially those related to danger. Are you saying these aren't necessarily memories, but rather a stimulus response? They must be carried down through the progeny somewhere, somehow.

Originally posted by Kruel
Makes sense, but that's just one example. What about newborn babies knowing how to swim? Or a chick knowing that a hawk is dangerous. Or a deer avoiding a wolf. Or animals avoiding lines where electric fences were previously set up (when it was the animal's parents, not themselves, who had ever experienced the danger of the electric fence). I can think of many other examples in nature without even researching.

Certain traits are clearly inherited, especially those related to danger. Are you saying these aren't necessarily memories, but rather a stimulus response? They must be carried down through the progeny somewhere, somehow.

All those examples are actually very easily explained and have been studied very well. I'll go through those you've listed, as they can be carried over to many, many other examples.

1) Newborns swimming: Newborns don't "swim" per se. They do know, however, to hold their breath, and then fight an opposing force keeping them in an anoxic (well, not totally anoxic but low oxygen) environment. For example, take a baby and blow in it's face. It wil,l automatically hold it's breath for a second or two. Same reaction, same reflex. I've heard that you should blow in a babies face before going underwater with it when teaching it to properly swim, that way they don't get a huge gulp of water. Babie will naturally hold their breath once underwater, and will flail about to try and get above water.

2) Chicks know hawks are dangerous for once reason: shadows. Many, many animalistic reflexes are triggered by light/dark differences. This is the same way fish know when a bird is above them, they see a sudden change in light. When a chick sees a sudden change in light, coupled with loud chirps from other chicks or clucks from a hen, it will panic and go into survival mode.

3) Deer don't just avoid wolves. They avoid any creature that smells or looks unfamiliar. Same goes for chicks, for that matter. Animals don't tend to congregate together unless the scent/appearance is familiar.

4) Animals avoid electric fences for several reasons. One, some believe, it that they have a dull electromagnetic sense, much like sharks and a few other animals whose names escape me. Also, as for calfs avoiding it, that's simple. They very rarely stray from the mother during their younger year(s), and learn a great deal from observing the other cattle. The herding behaviour also helps keep them away, I imagine.

So, basically, no, I don't think many behaviours are passed down through progeny, but there most likely are a few that are. I do think that a great deal of what we think are inherited behaviours can be otherwise explained, as you can see above.

Sorry if my answers were long or rambling!

Matt