I'd like to have the alien able to alter its genetics after eating a sample of the DNA. Would that be believable in an otherwise realistic setting? Or would it seem more like "fantasy" sci-fi instead?

I was considering what elements would make it believable. I decided it couldn't be a quick change, and mass would likely need to remain constant (except for some possible shedding of organic material, or heavy eating, to make small changes.) It also seemed like it should be painful or uncomfortable.

I'd like to include a believable, scientific explanation of how the alien does this. Any thoughts on what I might want to research would be wonderful. Any thoughts at all would be great, in fact.

Thanks in advance.
 

This would not be an instantaneous process, since the creature would have to essentially grow new tissues to fit the new morphology. I think it could gain or lose mass, actually. You could probably accelerate the growth process somewhat (there are many hormones that stimulate and accelerate cell growth). In shedding mass, it could cut the nutrients off of, say, an extra limb, and it would eventually die and fall off. Or the creature could eat it.

Hm... just had another thought here. Another way would be for the creature to go into a cocoon state, essentially self-digest itself, transfer the new DNA, and then begin to redevelop, as if from an embryonic state.

This might work better, actually, because even if the creature has the DNA, it wouldn't quite know how to "apply" it, i.e, where does the hair go? Where does the skin go? This sort of stuff, while all contained in DNA, is activated through a series of developmental hormones that are activated at various times in the embryonic state. I.E., one hormone early on causes the cells to differentiate into three layers, which will essentially become skin, organs, and skeletal tissue (or something like that, can't quite remember).

Btw, this info is coming from my undergrad studies in biology (my major) and genetics, as well as my continued interest in these fields.
 

Great ideas, annepin! I like the cocoon-state idea best.

One question, though: how would it retain memory and personality? If it's unlikely, that could be interesting, too. (I could see it leaving instructions nearby. "Next step: kill Mr. Jones. He knows too much. And pick up some milk--we're getting low." However, for story reasons, I'd prefer to keep its memory during a change.)

Also, what would be a reasonable cocooning period? I'm working with concepts so far--no story yet--but I think it would help story-wise if it could complete a change anywhere from a few hours to a day, but that seems a bit too quick to me.

Again, thanks! Great ideas.
 

How exact a change do you want? Are we walking mimicry, ala the octopus or a complete and fundamental duplication to where it would pass as the creature under scrutiny, like DNA testing?

If it's a mimic, then you could easilly have a creature that is somewhat amorphous and can modify is external appearance to fool those around them. A genetic doppleganger would be more difficult since at some level it would need to retain it's independent identity.

A puppetmaster variation could work as well, a parasitic symbiote, that uses the body mass of it's host and can modify that mass as needed.

You could also go the mental route, the creature simply projects the image they want into the viewers consciousness, this also creates some conflict since the creature would appear in it's natural state on video surveillance and such.
 

Personality and memory is a hard question, since the biological basis of neither is well defined. It could be an interesting study into the whole question of nature vs. nurture. Maybe debhoag could help out here...

Obviously, the brain would have to be rewired to accommodate the new body. However, perhaps there are analogous brain areas where it could "transfer" memories, or at least maintain a section of its brain intact where it stores this sort of thing. It might have to relearn some of this.

I think it would be interesting, too, to have a period where the creature is a little vulnerable because though it can create the form, it doesn't necessarily know how to use that form. Nor is that form fully developed. For instance, if it were to become a human, the genes would indicate the location of muscles. However, it's only by using these muscles for years, and training with them, that we're able to walk. Your alien, for instance, would not necessarily know how strong the muscles would need to be to support the weight, and when it awoke, wouldn't necessarily be proficient with their use. I think you could get around the first part maybe by the creature sort of analyzing its target species before hand--ah, biped, needs to have enough core strength to stay up right, needs massive quads, that sort of thing. And then it could increase muscle development based on _how_ it observes the species using the muscles and moving around.

Hope this makes sense! Feel free to email with additional questions.

[This message has been edited by annepin (edited September 24, 2007).]
 

Darn it! Now I'm going to be mulling this over all day!

[This message has been edited by annepin (edited September 24, 2007).]
 

But yeah, this can't be a complete transformation. The creature must retain it's own genetic code or it would be a one-way ticket. Human DNA, for example, does not contain any commands that would allow a human to change shape.

If it retains some part of itself when transforming, then this helps your memory/personality problem. I humbly suggest that the brain (or alien equivalent of a command center -- the queen nano?? ) is what stays the same from shape to shape. It would retain the alien's original DNA, original form, the ability to change form, personality, etc.

I'm not sure how realistic you want this to be. Genetics and the brain are both poorly understood. This has the disadvantage that at any time, some new discovery could completely undermine your entire theory. On the other hand, our limited knowledge will keep more readers from disbelieving whatever you do, even if it's far-fetched. You almost need to worry more about maintaining a suspension of disbelief (much like in a fantasy tale).

A couple of shape-shifting scenarios I have found unbelievable:

The chick on X-Men who can somehow, just by seeing another person, change the shape of her RETINAS to fool a retina scanner.

Changing mass. Changing SIZE can be somewhat believable if you explain that when in a larger form, the creature is less dense.

But what about other factors? I guess identical twins tend to look pretty identical (other than those factors), but those who are familiar can tell them apart. What about older twins? I just realized I only ever knew young twins.

So two twins who share the same DNA but live in different countries for forty years--do they look the same? The answer reflects how closely the alien could imitate a specific human being in appearance. I'll have to dig around and see what I can find.

Very interesting ideas. I think the limits will open up some interesting ideas for the story.

The stem cell idea is interesting.

Christine, I agree about lack of logic in some shape-shifting scenarios, such as you mention. I'm hope to account for all those early in the story-idea process.

I don't think I need a lengthy, details scientific explanation--just enough to create the feel that the idea has some thought behind it.

And I agree it has to retain part of itself, somehow. I don't think it needs to pass a DNA test. Just visual, retina and thumbprint would be enough--though I don't have a specific storyline in mind, yet. Is a genetic memory possible, encoding it's memories and personality within its DNA when it changes shape?

(and as a species--if they can sample DNA by tasting, for example, and can encode memories in DNA ... couldn't they share entire memories? Perhaps their entire communication-system could be done this way. Of course, humans don't record memories that way, so they could only do that among themselves. This is getting interesting!)

EDITED TO ADD: the memory question is interesting since my original idea was a shape-shifter with amnesia, thus having no idea who it was, what it looked like, or even what gender or species it might be. (Amnesia stories are common, but if anyone's seen this angle before, please let me know.)

(Edited again because I can't tell the difference between an angle and an angel.)

[This message has been edited by lehollis (edited September 24, 2007).]

[This message has been edited by lehollis (edited September 24, 2007).]
 

quote:

---

"Are we walking mimicry, ala the octopus ..."

---

I'll have to look into the octopus. I didn't know they could do any such thing. Thanks!

How does DNA account for hair length, for example? (Not counting the # of people who dye their hair.)

People who know twins well usually tell them apart by their personalities, which show in facial features, unless they have a birth mark or other distinguishing characteristic. I tend to think that if someone is not a twin, then people wouldn't be looking as closely to tell which one they were, and wouldn't be confused if it turned out to be neither. (Did that make any sense at all?)

It seems the shape shifter would need more than DNA to account for certain physical traits. Maybe after they get the basic blueprint right, they still have to tweak the form here and there? This might requires conscious concentration.
 

Either: don't explain it; or invent a creature with a different sort of physiology that is more robot-like than human. The biological part, including the intelligence is confined to a relatively small portion of the creature; this part does not transform, ever. The rest of the body, including the limbs are a more formable plastic-like or hydraulically controlled substance that the brain controls. If this idea appeals to you, you can work out the details of transforming from gorilla-size to wren-size.

[This message has been edited by WouldBe (edited September 24, 2007).]
 

If a person changed into a butterfly it would be one huge butterfly. Or an elephant-sized alien/magic being shapeshifted into a human, where'd the extra mass go?
 

The caterpillar crawls off somewhere safe because during metamorphosis it will be vulnerable (how does it know?) and becomes a pupa. Then it reduces its insides to soup (painful or uncomfortable, methinks), and reconstructs itself as a butterfly. That's 'managed' by special cells called 'imaginal buds' or 'histoblasts' (what wonderful words to conjure with) which maybe could be the way of retaining memory and personality from one shape to another.

Perhaps the histoblasts could 'copy' the target shape DNA by absorbing it when the alien eats the sample, and use it as a template when reconstructing from the soup.

More at http://www.earthlife.net/insects/lepidop1.html

Just a thought,
Pat
 

That kind of reminds me of Terminator 3 - where the Terminatrix identifies people by tasting their blood and doing a very quick DNA test. Plus in Terminator 2 we have the evil T-1000 that change his looks to anothers just by touching them. As well as the terminatrix doing that in T3.

So although most everyone else is thinking in biological terms, don't forget that you could use robots, cyborgs, or aliens to base your story on as well.

walt
 

Mimicry exists in a wide variety in nature and is basically just camouflage. True duplication is a different story.

An alien or engineered creature that mimics is not that hard to do. An underlying layer of bladders beneath the skin that can be inflated or engorged at will, chromatophores in the skin would allow color and tint changes, etc etc. You could disguise changes in mass by rearranging internal organs and filling interior bladders to generate volume. Pretty much a humanoid octopus now that I think of it, octopi would be a good basis for your creature.

There was a great special on I think Discovery, awhile back that dealt with humanities extinction and what would fill that evolutionary void at the top of the food chain. I believe a land based descendant of octupi was there projection.

 

TaleSpinner, the butterfly idea is what I was researching today, too. Annepin nailed it, huh?

So the only real variation from a butterfly is that it samples DNA before it enters pupa stage, during which it uses the genetic sample as a map for the new creature.

While a small portion of the creature lives through the process, sending out instructions to the "primal" cells, it's probably not enough to carry memory and personality over.

Thus, the idea of the creature writing memories and even personality into its genetics--even if only long-term memories--is still a good question?

I doubt anything on earth records memories in its DNA, so that would just have to be hand-waving. I'd just say that's what it does and move on. The reader would either accept it or not. But I do like the implications. (Especially since Amnesia is part of the story, so far.)

EDIT: Oh--and mass could change, I think. It doesn't have to recycle the entire body in that scenario. It could simply shed unnecessary "soup." Or it could gain mass by gorging itself before metamorphosis, since the process is already similar to self-digestion.

Extreme changes would still be unlikely, such as human to mouse, but some alteration then becomes possible.

Time is my biggest enemy. I'd like this to happen within a few hours, if possible. That would require tremendous energy. Perhaps it has to gorge anyway, if it wants to remain at its same mass. Gorge or shrink.

[This message has been edited by lehollis (edited September 25, 2007).]
 

it has nothing to do with DNA as much as it has to do with mind over matter.

if you were to take a sample of my DNA you would find no trace of wolf DNA in it. i would have never made it into the Army if there was any.

however my kind are working on DNA reprograming for the purpuse ofbring our kind back from the break of end of existence. we nolonger able to repruduce and we re hopefull that DNA reprograming will help.

anyway,

think of it as freezing a glass of water in the desrt during the hotest part of the day, but with out a frezer or any other cooling system only your mind. we just think of our other self and change. it is quick change no longer than 5min but qutie painfull.

Rommel Fenrir Wolf II
 

If one believes in Darwinian evolution, one would have to ask what the benefits to the alien life-form are of shape-shifting, especially if it cannot remember anything from one incarnation to the next. Butterflies only morph for sex, right?

If you want it to remember things, here's an idea. (I think.)

There was a theory -- maybe there still is, I'm not an expert -- that human memory is holographic. Also, if you cut up a hologram you have lots of smaller, identical (though perhaps degraded) holograms. (More at http://www.web-books.com/moBio/Free/Learning/Memory.htm)

So, suppose your alien shape-shifter uses a holographic memory structure, and suppose also there's a kind of cell that's a unit of holographic memory. And that the cells survive intact, swimming around in the soup. Then, when it reconstructs itself as the new shape, the imaginal buds organize things so that the memory cells clump together to form the new creature's memory. If things go awry in the soup, it loses some or all of its old memories. Evolution-wise, there'd be something to gain from changing shape and remembering, e.g. the deer can turn to a wolf and hunt with wolves, or the polar bear can turn into a buffalo and go south for the winter.

Just 2c,
Pat

[This message has been edited by TaleSpinner (edited September 25, 2007).]
 

My main idea is that this "Terran compound" as I called it, caused the DNA to be a whole lot longer than normal. The form and characteristics of the creature was based on the folds of the genetics, not the sequences in it. Folded one way, and you have creatures like us. Fold it another way and you have something that appears something like the creature in ALIENS. The advantage is that all the different forms are really all the same species.
Being virus-like, one could end up with genetics other than Terran, in the galaxy that are still viable with terrans.

This sort of thing could be an advantage to your story in that the creature might have developed the method to change form. It would not be changing the DNA, but instead changing the folds of the genetics, which would be less difficult than a total dna change, to become the same of the other forms.

For a less science fiction method, you might say that scientists changed the folds of DNA in an embrio and came up with a new creature. The alien has developed a method to refold its dna to become like new creatures, and then does a bit of natural skin color and texture change to become exactly like the creature it is copying once it sees one.
 

As for time... I'm still thinking of ways to get around the weeks. I think it could work--your creature would just go into hyper growth phase. Again, the energy cost would be huge. But in theory, cellular replication is pretty fast, and since it's not starting from a single celled organism, it might have an advantage.

About the memories encoded in DNA. I think this is possible, but this would assume that proteins, or protein products, are somehow responsible for memory, and I'm not sure what the going theory is these days. Again, Debhoag with her knowledge of psychology might be able to offer more guidance (and I'd be interested in hearing what she says!).

(and honesty, I'm just thrilled my knowledge is of use to anyone at all! )

[This message has been edited by annepin (edited September 25, 2007).]
 

Somehow, that one seemed believable to me and my daughter when we saw it.
 

There is an interesting thing on epigenetics in the Nova archives, discussing Histones and why the same DNA produces different structures at different times.

I guess I never had a problem with Odo and the t-1000. But it sounds like you're reaching for hard science, and not a universe where time travel is commonplace and every alien species is inexplicably humanoid. Well, Star Trek did try to explain it once, but it stunk.

[This message has been edited by Tricia V (edited September 25, 2007).]