Hope that helps...

[This message has been edited by tamalynn (edited November 06, 2002).]
 

DNA can establish parentage specifically, either paternity or maternity. It can also be used with a high degree of confidence descent from a grandparent or great-grandparent, if there are not a large number of siblings in the generation targeted (if your great-grandfather had more than about four brothers, it would be very difficult to establish by DNA testing that none of them could have been your actual great-grandfather).

Eventually, it becomes possible only to establish that you have some ancestral connection with the surviving family (or with the family of the target, if the a DNA sample can be obtained from the target). Depending on how many collateral lines of descent appear, you may be able to state with a high degree of confidence that you belong to a particular line of descent, but you cannot state with certainty that a particular person was your ancestor absent precise and reliable records of marriages, births, and other relevent information.

To summarize, yes a specific ancestor can be identified two or three generations "down the road." Yes, there is a point at which the genetic relationship becomes to tenuous to identify a particular ancestor, but that point is determined by how many collateral lines cannot be eliminated as possibilities (the more siblings or cousins of the target, the less certainty can be achieved). After more than four generations, even one same sexed sibling can make it impossible to identify the ancestor genetically.
 

Would you care to share the idea you are trying to work out? I'm very curious.

Regards,

Brian
 

TTFN & lol

Cosmi
 

A small number of clones are made from each of many people, the idea being that once in the population pool, the clones will be less likely to meet up with their physically similar donors. The resulting clones are mated with other clones to further obscure the DNA trail.

But would it? From what Survivor wrote, I don’t think clones from the same donor would qualify as true siblings or collateral lines.

 

Okay, clones are a different matter. A true clone should be genetically indistinguishable from the original organism or any other clone of the original. But if the originals were genetically diverse, then it should be possible to tell for several generations which original the parent clones came from, unless the group of original organisms includes some sets of siblings or other genetically similar individuals. But it would be impossible--no matter how few intervening generations "diluted" the genetic signature--to ever tell by genetic testing which clone was a parent, only the original organism could be identified.

I have no idea whether that helped at all. Here is a brief example:

Let's start with six originals
[*] Adam
[*] Bill
[*] Charlie
[*] Diane
[*] Ellen
[*] Francine
For convenience we will refer to them by letter; A, B, C, D, E, F.

We then make three clones of each, thus A1, A2, A3, and likewise till F3.

Genetic testing cannot tell any F from any other F, but can easily distinguish any F from any E, and the same holds true for each progenitor and associated clones.

We then marry up the clones, thusly:
A1-D1, A2-E2, A3-F3
B1-D2, B2-E3, B3-F1
C1-D3, C2-E1, C3-F2

Now the clones start to have children. We can establish, without question, which couple produced any child in this first generation, since only the children of--for example--A1-D1 will produce children with a mix of A and D genes (this presupposes that we are certain that none of the A's are commiting adultery with any of the D's, since we cannot tell a child of, say, A2 and D3 from a child of A1-D1, except by the fact that it will be D3 rather than D1 giving birth, and there would be no way at all to tell a child of A2 and D1 from a child of A1-D1). Note that in order to tell which child is which, we are totally dependent on knowing who married who.

It gets a bit more complicated as you go along, and after a few more generations it becomes completely impossible (when exactly that occurs depends on how many original genotypes you decided to clone--in our example, after three generations everyone has the same set of great grandparents from a genetic standpoint) In any case, since the clones are genetically indistinguishable, you must rely on records of who each particular clone had children with to identify the parentage.
 

If I understand you correctly-- and not to belabor the point -- although you may not be able to trace parentage to a clone, you could do so with the clone's original, up to some generational point.

Also, even with original siblings, even though you may not be able to identify the exact original sibling, you could identify the original family group.

I hope I got that right.
 

From what I'm gathering from these and other readings, since the Y chromosome stays basically unchanged from father to son, and you need male descendants to trace the DNA Y chromosome, it sounds like a clone with only daughters would effectively stop the trace.

I'll have to think about this.

[This message has been edited by Kolona (edited November 08, 2002).]
 

["The following" has been deleted, as my fallacy was pointed out for me. :)]

Luc

[This message has been edited by PaganQuaker (edited November 08, 2002).]
 

why, Luc, would not receiving the X chromosome of your father's mother have anything to do with whether or not you received information from her other chromosomes?

TTFN & ?

Cosmi
 

In each pair, one chromosome came from the mother and one from the father. So they aren’t identical.

Depending how the diploid cell divides through meiosis to form the haploid egg and sperm cells with only 23 non paired chromosomes (one randomly from each pair of the diploid), you get a different mix each time. Probability favors that there is representation from both of the father’s or mother’s parents in the genetic material he or she passes on.

I’m thinking (Very vague memory from Bio here) too that chromosomes sometimes swap material across the pairs. If so that fuzzies up the picture as well.

[This message has been edited by GZ (edited November 08, 2002).]
 

Of course, while there are lot's of alleles, which actually code for something, there is also a lot of gibberish that doesn't code for anything, but serves as a handy way of identifying where some of the genetic material came from. Because they don't code for anything they are highly variable and can be quite unique. Some of these are introns, occuring within a single allele, and thus presumably providing identification of where a particular allele originated (although it has been theorized that introns actually serve some esoteric purpose of gene regulation and thus are not actually random).

Anyways...I guess that information isn't really helpful
 

Shasta
 

Or, just possibly, it would only result in a mild case of Down's Syndrome. It's hard to tell without knowing more specifics. If the foreign DNA were alien enough, it may not be activated within the cell at all, thus having no effect on development (i.e. if the chromosome came from an actual "alien" with basically different cellular mechanisms, the extra chromosome might simply be ignored).
 

Shasta

*edit: Presuming, of course, that the person doing the coding had the technology to do so. I doubt we're anywhere near being able to do that now.

[This message has been edited by DragynGide (edited November 12, 2002).]
 

The question in this case is why you would do that. If you code the chromosome so that it has no "tags" (sequences that act as hooks or keyholes or whatever metaphor you prefer), then it will never be cleaved by the cellular machinery and should never do anything (it might get in the way during meiosis, but this wouldn't harm the original organism, only progeny would be affected). Hmmmm, that's a suggestive possible use, but I'm not sure it would work. At least some of the time, the thing wouldn't get in the way, and if it did, the result should be failed meiosis, not mutant genes for the progeny. It would be a clumsey mechanism, in any case.

What exactly do you want this extra chromosome to do?
 

Hence you have a true, scientifically explainable shapeshifter. How the creature would get the massive amounts of energy needed to make this shift in a short time is another story entirely.

Shasta
 

If you want a shapeshifter, then you need to go with an enhanced slime-mold or something of that nature, that already has the ability to physically transform from one shape (and form) to another. You would need to engineer the genetics to provide it with high strength connective and structural proteins that could be easily recycled within the organism, proteins analogous to those used in sensory organs, and some level of individual cellular sensitivity to a nervous system (which would be easier to provide seperately...actually, the whole thing would be easier to build from scratch, without using biological material, but getting the nervous system would be darn near impossible using genetic engineering).

If what you are looking for is the ability to genetically test as belonging to two or more different species, then the thing just can't be based on genetic material at all, and that's all there is to it.

Maybe I didn't understand your scenario, though.
 

I'm trying to explain, as realistically as possible, how werewolves could be created and how they would function, as a self-sustaining "race".

Their progenitors would have fantastically advanced genetic technology.

A werewolf would contain, within themself, both a wolf and a human set of DNA, between which they could transform when triggered by certain conditions (like, for example, a sudden adrenaline flow). The body would have extremely heightened capabilities for cannibalism and reformation of tissues as well as a highly efficient digestive system, and even then I imagine that the energy cost of such a transformation would be astronomical.

The idea I've been working with for how werewolves propagate and come into their own is this: a werewolf mates with a human, providing three sets of chromosomes to create a fetus. Only the two matching ones are used-- something about the werewolf's enhanced genetics must allow the body to ignore the third set but replicate it into every cell. The third set of chromosomes is ignored entirely until another, matching set is introduced from an external source at puberty. The fourth set is delivered, as I said above, by a highly modified virus, which also gives the body the information and ability to handle both DNA sets (without self destructing, I hope!) and to change between the two.

The virus itsself actually carries two sets of chromosomes, one for wolf and one for human, and being a "smart virus", it injects one and the other disintigrates along with the virus package once it has served its purpose. The newly complete werewolf then begins to manufacture the same sort of virus, composed of mixtures of its own chromosomes (much like sperm, but with that extra info), in its salivary glands. Thus other potential werewolves-- people with that third set of chromosomes waiting to be activated-- must be bitten (or even possibly just kissed), in order to become full-blown werewolves themselves.

Please, do poke holes. But also, please PLEASE offer other possible solutions. This does, after all, have to work.

Shasta
 

Since you are going with the idea that a viral component is involved anyway, what I would suggest is that the human is genetically normal, but is host to a symbiotic organism (like mitochondria, but different ) that is capable of reshaping the body to a certain degree under certain conditions (adrenaline would be an ideal trigger). It would only have to do three things. 1st, provide cellular energy, possibly by increasing the intracellular ATP levels and extracellular oxygen and glucose pathways. 2nd, it would have to act to heal damaged tissue, possibly by templating healthy cells and mass producing them while acting as or providing a synthetic connective tissue substrate. 3rd, it would have to be transmissable by saliva to other compatable human hosts (I won't bother to detail that one, most microbal organisms that live in humans can pull this off).

The first and second features would increase strength and endurance, as well as resulting in rapid growth of hair, fingernails, skin etc. (just how rapid is a matter I'll leave to you, although you might want to play with the idea that it takes a couple of days of "werewolfiness" to get the full effect of long claws and shaggy hair and bestial skin--as well as the idea that returning to human involves razor, emory board, and exfoliants liberally applied ). The third feature would result in the transmission of the symbiont via the bite of the werewolf. Sorry, but I can't do fangs plausibly, unless you want them to be permanent.

There is no real need to explain such an organism as a genetically engineered creation either (though it could be). Many microbal organisms in nature have evolved symbiotic relationships with host organisms (current theory holds that this is where mitocondria--and indeed, all the other features of the eukaryotic cell--come from). Much of your digestion relies on the assistence of microbal communities, both in your saliva and in your gut, and termites would quickly starve without the microbes that allow them to digest cellulose. A symbiotic organism of the complexity described above might well be more selective in its requirements for a particular host (the genetic compatability thing) than is usually the case, but since some specific microbes are limited to a single species or sub species, this would not be unrealistic.

But I'm not sure I understand why it has to "work" if your doing a story about werewolves, since they are an accepted convention. Unless you are planning to have a scientist (possibly a werewolf?) investigating the biological mechanism underlying the transformation as part of your storyline.
 

TTFN & lol

Cosmi

[This message has been edited by Cosmi (edited November 22, 2002).]