Well are they?
If you had two same sex, physically identical twins is this the same thing physically/biologically (in terms of results) as if you had cloned one of them or do even “identical” twins have some physical and mental differences?
Well are they?
If you had two same sex, physically identical twins is this the same thing physically/biologically (in terms of results) as if you had cloned one of them or do even “identical” twins have some physical and mental differences?
Meant to post this link which originally inspired the question. It seems cloning farm animals is already a pretty matter of fact reality and a growing market. I had no idea it was this far along.
http://www.washingtonpost.com/wp-dyn/articles/A51619-2001Mar24.html
Cloned Cows Are Fetching Big Bucks
Dozens of Genetic Duplicates Ready to Take Up Residence on U.S. Farms
By Justin Gillis
Washington Post Staff Writer
Sunday, March 25, 2001; Page A01
Yes they are clones. Remember identical twins start out as ONE cell that divides.
Are the twins exact? No. Would clones be? No.
There are too many invironmental differences involved. For example many identical twins show a distinct “sidness.” For example on will be left handed one right handed. One have a natural part on the right the other on the left and so forth.
Twins fingerprints aren’t identical.
That is why it cracks me up when people say no two snowflakes are alike. What, if anything in nature is exactly alike.
People fear clones as they picture armies of mind controled zombies as the original would have some control over his “CLONES.”
The real fear comes in well we only want blonde hair blue eyed babies and now we don’t have to abort the brown haired ones to get them…That kind of theory.
The fact is take a look at identical twins. One may be smarter than the other, one may even be prettier. One may be a little bit country one a little bit rock ‘n’ roll.
Identical twins, as a whole, are very much alike. But picked apart there differnces are great.
Yes, I think indentical twins are exactly the same as clones (except for maybe some differences due to the process: separation of cells vs. inserting a nucleus from a somatic cell into an egg cell).
Indentical twins are indentical genetically: not physically and mentally. They are only similar in those respects because of their common genetic heritage. Clones are also only indentical genetically. They are similar physically and mentally for the same reason as indentical twins.
In fact, “clone” is a synonym for “indentical twin.” But human identical twins usually aren’t referred to as clones.
Per your example the twins aren’t really exact copies. Wouldn’t a clone be a much closer copy in that case?
Pre-and post natal environmental factors affect innate sidedness? Isn’t this inherent to the genome? Also why wouldn’t clone fingerprints and hair parts be identical to the cloned original. I don’t see how fetal environment could affect these things.
If you have a pair of monozygotic (“identical”) twins, then genetically speaking, they are clones of each other. The “nature” part of their makeup is identical. However, you can have identical twins that have different physical characteristics, such as weight or height, due to the influences of the environment they live in (“nurture”). They can also have different personalities and interests.
So, while genetically, they are the same, they are going to end up being different, personality-wise, because of the different experiences each twin will have.
Identical twins are different from clones. Twins also share the same mitochondrial DNA (DNA outside the nucleus belonging to the mitochondria, the cell’s powerhouse). Mitochondrial DNA is passed down solely by the mother, since the offspring recieves mitochondria from the egg cell. Identical twins, since they come from the same cell, have identical mitochondrial DNA. Clones, unless they were made using eggs from the same woman (or from one of her maternal relatives who also share her mtDNA makeup) who donated the DNA, wouldn’t share the DNA donor’s mitochondrial DNA and would thus also be genetically different.
An excellent point, though the vast majority of mitochrondrial genes are never expressed outside of the mitochrondria and so would have a very minimal effect on the whole animal.
GilaB’s points are very valid, but I have a nitpick with the use of the word “clone.” Identical twins are clones in the biological sense of the term. Gila seems to be using the term “clone” only to refer to those produced artificially in a laboratory. In fact, as Gila correctly points out, identical twins are more alike than laboratory-produced clones because they share not only nuclear but also mitochondrial DNA. Laboratory clones, if they are produced by different mothers, would be even less alike than identical twins, because identical twins also share the same womb and thus many developmnetal variables during fetal development.
Identical twins are not completly identical because of environmental influences. Laboratory clones would be expected to be considerably more different from one another as individuals than identical twins are for both genetic and environmental reasons.
Here’s a nit to pick…
Clones would be different in age, twins would not.
Although one could clone a cell from a very early stage so this difference would be infetesimal. But if you were to clone ME, there would be a 28 year difference between US. Weird, I could watch myself grow up. sniff
Since astro said something about twins of the same sex which are identical, it would appear that he may not understand that identical twins have to be of the same sex, but that not all same sex twins are identical. Since that isn’t my field, will someone please comment. My interest is that I have boy/girl twins.
What initially piqued my interest in this question is this quote from One False Move by Harlan Coben: “If you clone yourself, and then have sex with yourself, is it incest or masturbation” (52)?
My first thought was incest, since I thought that "clones" could be no more similiar, at least genetically, than identical twins. This issue seems to have been resolved in this thread. It seems that referring to a clone as "myself" or as "a little version of myself" or "mini-me" would be completely inaccurate, or at least as inaccurate as referring to one's identical twin as "myself."
My only problem with this subject remains the fingerprint issue. I assume that fingerprints are not determined by one's genes, as it has been stated in this thread that identical twins do not have identical fingerprints. I then surmise that "clones" do not have identical fingerprints either. Therefore, how are one's fingerprints determined? Is it completely random (just the way the skin grows), or is it determined sometime in the environment, most likely in the womb? Please enlighten me.
-James
Actually there are several mitochondrial mutations that have severe effects on the whole animal by decreasing the rate and efficiency with which ATP (useable energy) can be produced.
IIRC, identical twins have very very similar fingerprints (about 90-95% similar, although I learned this about five years ago and haven’t really thought about it since, so my numbers may be off). The implication of this is generally thought to be that a large part of fingerprint patterning is genetic, but that it’s influenced by factors in the womb, such if the fetus is touching anything as its fingerprint patterns are laid down.
Sex with your clone would definitely be incest. Although you wouldn’t be exactly genetically identical (because of the mitochondrial DNA stuff that I mentioned earlier), you’d still be an awful lot more similar than ordinary siblings. Yes, you’d be quite different, having presumably been raised at different times, probably by different people, but incest isn’t because of environmental factors. It’s a very bad idea because of genetic reasons - any wierd little recessives that you carry are very unlikely to also be carried by an unrelated person from the population, but are definitely carried by your clone, giving your offspring a very high likelyhood of inherited genetic disorders.
Of course, it’s a bad idea for a bunch of other reasons too, but let’s not go there ;).
I’d like to know how you get an offspring from sex with your clone, given that you will be the same gender.
Here’s the master himself on the question of identical twin fingerprints:
Do identical twins have different fingerprints?
Arjuna34
[flagellation]I blush, I blush! How stupid of me! Really really stupid! I should retroactively flunk both Genetics and Developmental Biology![/flagellation]
*Originally posted by kniz *
**Since astro said something about twins of the same sex which are identical, it would appear that he may not understand that identical twins have to be of the same sex, but that not all same sex twins are identical. Since that isn’t my field, will someone please comment. My interest is that I have boy/girl twins. **
Ummm yeah… I understood that. I made the (obviously somewhat redundant) “same sex” note to make it explicit that I was talking about physically identical twins and not boy/girl twin pairs.
*Originally posted by astro *
**Per your example the twins aren’t really exact copies. Wouldn’t a clone be a much closer copy in that case? **
With both synthetic (laboratory-produced) and natural (identical twins) clones the only thing really being copied is the instructions for making a living creature. Because this is a complicated process, each time you run the “program” it comes out just a touch different.
Think of those paint-by-number sets - if you take two with the same picture and give one to me to paint and one to my sister, after were done you can plainly see they are the “same” picture but if you look closely you’ll see minute differences that would allow you to distinguish one from the other. Same instructions, slightly different results.
**Pre-and post natal environmental factors affect innate sidedness? Isn’t this inherent to the genome? Also why wouldn’t clone fingerprints and hair parts be identical to the cloned original. I don’t see how fetal environment could affect these things. **
No one knows 100% why a person winds up right or left handed. There is some indication that some folks are “hardwired” to be one or the other, but also some indication that other people aren’t wired to be either but become one or the other due to environmental factors. Then you have freaks like me who are “mixed dominant”, meaning I’m a rightie for some things and a leftie for others, and even those who are truly ambidextrous. So, it may be “inherent” in some cases and not in others.
Fetal environment can be a factor. The human system can switch “handedness” if given enough incentive - for instance, if you’re right handed and get your right arm chopped off your left hand can learn to do things your right hand used to do - such as write. If damage occurs to the fetus before birth (lack of sufficient oxygen, for instance, at a crucial time in development - like all development time isn’t crucial) a fetus that was supposed to be right-handed might switch over to being a leftie. Or vice versa.
As for fingerprints – rather than program in exacting detail the unique patterns on the skin, it appears that fingerprints are a fractal-generated phenomena. Each time the “program” runs it follows the same basic routine but the results are subtly different. This results in patterns unique to each and every human being (including genetically identical people) without taking up a lot of room on the genome with the petty details.
*Originally posted by astro *
**Ummm yeah… I understood that. I made the (obviously somewhat redundant) “same sex” note to make it explicit that I was talking about physically identical twins and not boy/girl twin pairs. **
It’s still not clear that you understand, though. Fraternal twins (which is to say non-identical twins) do not have to be one boy and one girl. Two of my nephews are fraternal twins, for instance. Fraternal twins are, genetically, no more alike nor different from one another than any other two siblings… they just happen to be wombmates for nine months. As such, fraternal twins can be two girls, two boys, or one boy and one girl, just as two non-twin siblings can be sisters, brothers, or one of each.