Identical twins

[Dioklecian]

Do identical twins have the same type or different ones?

[Dioklecian]

[Dioklecian]

[Dioklecian]

[Dioklecian]

[Dioklecian]

Dear Yahoo!:
Do identical twins have identical DNA?
Ben
Evans, Georgia

Dear Ben:
A search on "identical twins DNA" led us into a fascinating world of genetics, cloning, and the old nature vs nurture debate.
As we soon learned, identical twins, formed when one fertilized egg splits, are the only people in the world with identical DNA. Fraternal twins, on the other hand, are formed when two different eggs are fertilized. Genetically speaking, fraternal twins are no closer than normal siblings, sharing only about 50% of their genes.

Although identical twins have the same genotype, or DNA, they have different phenotypes, meaning that the same DNA is expressed in different ways.

Traits determined by phenotype, such as fingerprints and physical appearance, are the result of "the interaction of the individual¿s genes and the developmental environment in the uterus." Thus, a DNA test can't determine the difference between identical twins, while a simple fingerprint can.

[Dioklecian]

The Genotype/Phenotype Distinction
First published Fri 23 Jan, 2004
The distinction between phenotype and genotype is fundamental to the understanding of heredity and development of organisms. The genotype of an organism is the class to which that organism belongs as determined by the description of the actual physical material made up of DNA that was passed to the organism by its parents at the organism's conception. For sexually reproducing organisms that physical material consists of the DNA contributed to the fertilized egg by the sperm and egg of its two parents. For asexually reproducing organisms, for example bacteria, the inherited material is a direct copy of the DNA of its parent. The phenotype of an organism is the class to which that organism belongs as determined by the description of the physical and behavioral characteristics of the organism, for example its size and shape, its metabolic activities and its pattern of movement.

It is essential to distinguish the descriptors of the organism, its genotype and phenotype, from the material objects that are being described. The genotype is the descriptor of the genome which is the set of physical DNA molecules inherited from the organism's parents. The phenotype is the descriptor of the phenome, the manifest physical properties of the organism, its physiology, morphology and behavior.

The concepts of phenotype and genotype also demand the distinction between types and tokens. As the words “genotype” and “phenotype” suggest, these are types, sets of which any given organism and its genome are members, sets defined by their physical description. Any individual organism and its genome are members of those sets, tokens of those types.

[Rocky]

Quite clearly, the same. They are born with the same brain. There's is no possible way it could be the other way around, if they are identical.

[aestrivex]

Quite clearly, the same. They are born with the same brain. There's is no possible way it could be the other way around, if they are identical.

except that many identical twins exhibit vastly different characteristics...

[Creepy-bg]

I remember seeing on a MBTI site that Ashley and Mary Kate Olsen are both INTPs... I don't know if this was a tested thing or just a guess. They both seem the same in some ways and yet different enough in others. But then the similarities and INTPness may just be a result of living a sheltered, behind the walls of money, life. Either way I'd have sex with either of them (although the anorexic one seems more fun)

/edit ehhh sorry... ignore that last part (we don't want a repeat of the conjoined twins thread :wink: )

[Rocky]

Quite clearly, the same. They are born with the same brain. There's is no possible way it could be the other way around, if they are identical.

except that many identical twins exhibit vastly different characteristics...

If they grew up in different enviorments, sure, but only on the ouside, the "persona", NOT the brain.

[aestrivex]

Quite clearly, the same. They are born with the same brain. There's is no possible way it could be the other way around, if they are identical.

except that many identical twins exhibit vastly different characteristics...

If they grew up in different enviorments, sure, but only on the ouside, the "persona", NOT the brain.

that brings up an interesting question. is personality determined by the brain or what? genetically the brain is identical, but the idea that this will lead to two identical individuals ignores the chaos factor.

[Dioklecian]

Quite clearly, the same. They are born with the same brain. There's is no possible way it could be the other way around, if they are identical.

except that many identical twins exhibit vastly different characteristics...

If they grew up in different enviorments, sure, but only on the ouside, the "persona", NOT the brain.

I don't think that they are born with the same brain. They have the same DNA but its' expressed differently.

http://plato.stanford.edu/entries/genotype-phenotype/

[Rocky]

Personality is related to the brain. For example, brain scans of people show that people who show signs of "inhibition" (i.e. what we would call "introversion") "light up" more areas in the back of the brain whereas people who are completely uninhibited don't.

I think type is whatever part of you that you're born with (plus other genetic variations that alter type-within-a-type, or "subtype"), and everything else is how you are affected by your enviorment. The line is hard to draw, though.

[Dioklecian]

Personality is related to the brain. For example, brain scans of people show that people who show signs of "inhibition" (i.e. what we would call "introversion") "light up" more areas in the back of the brain whereas people who are completely uninhibited don't.

I think type is whatever part of you that you're born with (plus other genetic variations that alter type-within-a-type, or "subtype"), and everything else is how you are affected by your enviorment. The line is hard to draw, though.

Well do you think that fraternal twins like those in pictures have the same type or different types? (It doesn't matter why).

[aestrivex]

i don't know enough about the biology of the brain to really pursue this discussion, but clearly identical twins can be of different types and very different people.

[Rocky]

Personality is related to the brain. For example, brain scans of people show that people who show signs of "inhibition" (i.e. what we would call "introversion") "light up" more areas in the back of the brain whereas people who are completely uninhibited don't.

I think type is whatever part of you that you're born with (plus other genetic variations that alter type-within-a-type, or "subtype"), and everything else is how you are affected by your enviorment. The line is hard to draw, though.

Well do you think that fraternal twins like those in pictures have the same type or different types? (It doesn't matter why).

Fraternal? Any type.

[Dioklecian]

Personality is related to the brain. For example, brain scans of people show that people who show signs of "inhibition" (i.e. what we would call "introversion") "light up" more areas in the back of the brain whereas people who are completely uninhibited don't.

I think type is whatever part of you that you're born with (plus other genetic variations that alter type-within-a-type, or "subtype"), and everything else is how you are affected by your enviorment. The line is hard to draw, though.

Well do you think that fraternal twins like those in pictures have the same type or different types? (It doesn't matter why).

Fraternal? Any type.

I mean: if you are ISTP and you have a fraternal twin, would that twin be ISTP also? Or he/she have a different type?

[Rocky]

And I said, it could be the same or different. Fraternal twins aren't really twins the way you're thinking of them; they are as close as ordinary siblings.

[Joy]

It seems that most of the identical twin sets I've known have been made up of one extrovert and one introvert.

[normal]

i dont believe that twins have the same type. Its almost more illogical like to say that a mother (ISTP) and father (INTP) have a probability of 50% to have a son/daughter ISTP-INTP.
Obvious its an evolution-adaptation subject. They can have the same brain, but its development always is going to be different even if they have the same education. Any thorn turns aside the way they said here.

[eunice]

I wonder what happens when u get a conflictor as your identical twin?

[Dioklecian]

And I said, it could be the same or different. Fraternal twins aren't really twins the way you're thinking of them; they are as close as ordinary siblings.

Sorry, I meant Identical twins, as the topic.

[Exodus]

I remember seeing on a MBTI site that Ashley and Mary Kate Olsen are both INTPs...

Bullshit. edit: I mean the typing. (Although I should probably research it just to make sure.)

Personality is related to the brain. For example, brain scans of people show that people who show signs of "inhibition" (i.e. what we would call "introversion") "light up" more areas in the back of the brain whereas people who are completely uninhibited don't.

I think type is whatever part of you that you're born with (plus other genetic variations that alter type-within-a-type, or "subtype"), and everything else is how you are affected by your enviorment. The line is hard to draw, though.

Well do you think that fraternal twins like those in pictures have the same type or different types? (It doesn't matter why).

My brother and sister are fraternal twins, INTp and ESFj respectively.

i don't know enough about the biology of the brain to really pursue this discussion, but clearly identical twins can be of different types and very different people.

Are you basing this on experience or what?

The only identical twins I have had a chance to type were quite similar. Both ENF, and likely both ENFj. Somehow I don't think this is a coincidence.

I wonder what happens when u get a conflictor as your identical twin?

Hilarious antics ensue.

[Dioklecian]

The only identical twins I have had a chance to type were quite similar. Both ENF, and likely both ENFj. Somehow I don't think this is a coincidence

This is very interesting. Do you think that identical twins have the same type always?

[aestrivex]

The only identical twins I have had a chance to type were quite similar. Both ENF, and likely both ENFj. Somehow I don't think this is a coincidence

you should acknowledge that a sampling like that leaves ample room for coincidence.

[Exodus]

The only identical twins I have had a chance to type were quite similar. Both ENF, and likely both ENFj. Somehow I don't think this is a coincidence

you should acknowledge that a sampling like that leaves ample room for coincidence.

Duh.

Whereas your sampling was...?

The only identical twins I have had a chance to type were quite similar. Both ENF, and likely both ENFj. Somehow I don't think this is a coincidence

This is very interesting. Do you think that identical twins have the same type always?

I don't really know. But it did seem strange to me.

[aestrivex]

The only identical twins I have had a chance to type were quite similar. Both ENF, and likely both ENFj. Somehow I don't think this is a coincidence

you should acknowledge that a sampling like that leaves ample room for coincidence.

Duh.

Whereas your sampling was...?

admittedly, i don't know any. but, statistically, your claim is hardly more useful. it is absurd to make generalizations based on the results of one case, which appears to be your argument here.

[Exodus]

This is very interesting. Do you think that identical twins have the same type always?

I don't really know. But it did seem strange to me.

[Dioklecian]

So do we have an agreement: do identical twins have identical types?

[That Guy]

In my year during high school, there were two sets of identical twins and a set of fraternal twins.

I think it was quite obvious that the fraternal twins were different types.

The identical twins seemed to be similar to there respective identical twin, although i didn't really get to know them enough to tell.

The argument that identical twins can be fairly different does not disprove that they are the same type. I know quite a few ESTp's, and they can be very different from each other.