Me and My Clone

October 13, 2009 3:53 PM

If you (a human) were cloned, would your clone look exactly like you?

A kid at the library today had a patch on his bookbag saying 'My Clone Did It.' But would your clone necessarily look identically like you, or sufficiently like you to fool the authorities? As I understand it, twins have identical DNA but they don't always look like one another.

Is my clone always my identical twin?

posted by orrnyereg to science & nature (26 comments total)

No. For one think your clone would look a lot younger. I would think the differences would be a lot greater then differences between identical twins, because in-utero hormone levels have a pretty big impact on people.
posted by delmoi at 3:57 PM on October 13 [2 favorites has favorites]

Nope. Your appearance, or phenotype, is the result of interactions between your DNA, or genotype, and environment. Since you and your clone would necessarily have different interactions with the environment (including the in-utero hormone levels delmoi mentions, but also just through living), your phenotypes would vary to that degree.
posted by amelioration at 4:01 PM on October 13 [1 favorite has favorites]

Just like with identical twins, your clone will have different fingerprints than yours.
posted by fings at 4:02 PM on October 13

A clone could look somewhat different. Identical twins have different fingerprints. Other phenotypic differences would be that much more likely with a clone, since it would incubate in a different uterine environment.

Also, the clone would have a goatee.
posted by adamrice at 4:03 PM on October 13 [31 favorites has favorites]

No. I've got a bunch of tattoos.
posted by box at 4:06 PM on October 13 [4 favorites has favorites]

Unless my clone face-plants off a swing into gravel at age three, they won't have a scar under their right eye. And I would hope they develop better posture.
posted by girlgenius at 4:08 PM on October 13 [1 favorite has favorites]

Is my clone always my identical twin?

Unless you get into some sci-fi shizzness, more or less, yes.
posted by Cool Papa Bell at 4:09 PM on October 13

No, not exactly. And delmoi raises a very good point regarding the similar environment that monozygotic twins get that you won't. The Wikipedia article mentioned by Cool Papa Bell raises another good point—you won't even necessarily be genetically identical. But you will be very, very close.
posted by grouse at 4:16 PM on October 13

Here's a cat and clone. Notice all the orange on Rainbow (the original) that CC (the clone) doesn't have, and the gray spot on CC's left foreleg. (We're not cats, of course, but I thought it was neat that this answer has been demonstrated in another species.)
posted by Zed at 4:29 PM on October 13 [1 favorite has favorites]

As I understand it, twins have identical DNA but they don't always look like one another.

Others have already covered the answer pretty well, but just so we're on the same page here: identical twins have [virtually] identical DNA and look pretty much the same. Fraternal twins have DNA that is only as similar as any other set of siblings, and can resemble or not resemble one another as much as any set of siblings. An identical twin is the equivalent of a clone that happens to undergo gestation with you.
posted by telegraph at 4:41 PM on October 13

The cloned cat's coat colour is the result of random x-inactivation during development and is not really a fair way to compare physical similarity of cloned cats.
posted by sciencegeek at 4:45 PM on October 13 [1 favorite has favorites]

The cloned cat's coat colour is the result of random x-inactivation during development and is not really a fair way to compare physical similarity of cloned cats.

How is it not? It is an excellent example of non-genetic factors that might cause a clone to not look exactly like the original.
posted by grouse at 4:57 PM on October 13 [5 favorites has favorites]

Cloned phalenopsis orchids can look radically different due to slight genetic mutations.
posted by aquafortis at 5:06 PM on October 13

A clone of you would look as much like you as an identical twin of you would, except for the age difference of course. Also there would probably be differences due to congenital differences, since your clone would presumably not be subject to the exact same conditions in utero.
posted by peacheater at 5:09 PM on October 13

Identical female twins have different x-inactivation. Identical female twins look pretty much the same. Cats are unusual in that they have a very visible x-inactivated gene.

Also, if you want to avoid this phenomenon, we can avoid female twins and focus on male twins. Yes there are imprinted genes in males as well, but not entire chromosomes as in female twins.

I think it would be more informative to talk about DNA methylation, histone modifications, maternal mRNA, miRNA and probably a few other things. I'm not enough of an expert to go into this on an organismal level.

I just thought that the example of calico cats was not a good one.
posted by sciencegeek at 5:12 PM on October 13

It's so lovely having my assumptions vindicated. Thanks, all!
posted by orrnyereg at 5:54 PM on October 13

Please define "able to fool authorities." Ultimately, anyone who spends enough time with any set of identical twins will always be able to tell them apart, pending a deliberate effort to confuse people or deliberate refusal to make an effort. Parents, teachers, sibs and spouses of identical twins will verify this.

However if you are asking if the DNA of identical twins/clones will be sufficiently similar to fool authorities about paternity or murder or sample switches for genetic tests, then yes, barring extremely unusual circumstances, clones/identical twins will not be differentiated for most conditions by most current testing methodologies.

However, identical female twins do not look always "pretty much the same." Googling "discordant x-linked phenotype in female identical twins" without quotes generates numerous cites of differences in X inactivation leading to genetically identical female twins with widely variable phenotypes for X-linked genes such as HPRT, hemophilia, IP, OTC, DMD, x-linked rickets, and, I would expect, virtually any disease associated gene on the X chromosome. Many of these will have noticeable effects at physical level as well.
posted by beaning at 5:56 PM on October 13 [1 favorite has favorites]

Please define "able to fool authorities." Ultimately, anyone who spends enough time with any set of identical twins will always be able to tell them apart, pending a deliberate effort to confuse people or deliberate refusal to make an effort. Parents, teachers, sibs and spouses of identical twins will verify this.

Please, because I was contemplating an AskMe about this very topic.
posted by Lucinda at 6:01 PM on October 13

*annecdote* friends of mine are twins, and I haven't had any trouble telling them apart from late primary/early highschool or so. Now, I can tell who they are just by looking carefully at the face.

Another friend was horribly embarrassed when he mixed them up on their 21st birthday, so made an effort to learn to tell them apart. He now can.

Of course, they get mixed up all the time by other people who aren't paying attention, including teachers at school.

*side note* isn't there a really annoying short story where twins take turns confessing at each other's trial for murder? (annoying because the story never resolves.)
posted by titanium_geek at 6:34 PM on October 13

I work with a database of driver's license photographs (with thumbprints, which tend to be of pretty poor quality), and twins give us fits sometimes. When the prints are really bad / nonexistent it's really hard to tell (sometimes people will have a fraudulent identity with the same birthdate, presumably with forged documents that are made to order). It's more common for people to get fraudulent licenses or IDs in their non-twin brother or sister's name, but twin fraud certainly happens too. Clones would probably look like fraud if it weren't for the fingerprints and the age difference.
posted by marble at 6:39 PM on October 13

Piggybacking here- would your clone have any genetic birth defects that you had?
posted by xmutex at 7:32 PM on October 13

Xmutex, the quick answer is yes but the phenotypic effect might vary depending upon the nature of the genetic disease. I would expect some degree of variation especially with a genetic disease which was mitochondrial, X-linked or heavily influenced by environmental factors. The more interesting answer would explore reproductive vs therapeutic vs germ line vs somatic cloning and that's beyond my brain right now. The Human Genome Project has an overview of cloning at this site with links at the end. The Utah site is also good at first glance and much more user friendly.
posted by beaning at 8:47 PM on October 13

Some people here are arguing that monozygotic twins show phenotypic variance, and others are arguing that clones would show even more phenotypic variance than monozygotic twins. I think the latter claim is a lot more interesting. Commenters here are on to a good idea by suggesting that clones might be more dissimilar from one another than monozygotic twins because they would not share a uterus and uterine development is really important, but I don't think anyone has offered any evidence for the claim. This is a question about the developmental plasticity of certain overt phenotypic features in humans. Have there been any studies on this topic? Have there been, say, any monozygotic twins who were raised in separate test tubes, or even separate uteri?

I think the jury is out on this question and we just don't have the ability to say.

I've heard that some evo-devo guys think that the uterine environment is really important for phenotypic development -- to the extent that if you were to have a woolly mammoth fetus gestate inside a female elephant, it would end up looking more like an elephant than looking like whatever mammoths looked like in the past. On the other hand, cloned bulls and sheep look almost identical to the originals (according to people who can discriminate between different bulls and sheep). Why should humans be any different?
posted by painquale at 10:32 PM on October 13

In my observation, identical twins often have different teeth, skin markings (moles, freckles, etc), and slightly different nose lengths and eyebrow heights. So I'd assume a clone would have a scattering of differences like that as well.
posted by twistofrhyme at 11:51 PM on October 13

No one has mentioned factors around body shape. I know a couple of pairs of identical twins who look very different because of their exercise/eating habits.
posted by hworth at 3:06 AM on October 14

Well, I can't say the movie was all that great but The Island presented some psuedo-science for cloning. The main purpose of the clone however, is for organ harvesting for the rich "donor" who wanted to a genetic "backup" As for exercise/eating habits.... the Island kept them all moving and working and fit it seemed.

I can't think of them right now, but there were similar movie(s) or book(s) which got into transplanting memories or brains or some such that were interesting diversions on the reasons behind cloning.

I suppose if you had a society or setup where you monitored all the uterine development and potential variances, but that's really going sci-fi for that to be done on a mass scale anytime soon.

Fun question to think about though, thanks!
posted by emjay at 9:23 AM on October 14