How do identical twins always look the same?

Question

eh hem... when i see identical twins... they are... identical... doesnt one ever get heavier or lighter?? do they eat the same things at the same time?? how can they always be the exact same?

Answer 1

The reason they are identical is that  one sperm fertilises one egg which in turn divides in two, resulting in two identical foetuses, which, in turn results in the birth of to identical babies. As they get older the environment they each live in, have subtle effects on their individuality and preferences, but, they always remain very similar, because they are identical and in effect clones of each other.

Answer 2

well i know 2 twins called billy and scott and billy always war somthing bule and scott war somthing scarlett(red) becase scott started with s and so did scarlett and billy starts with b and so does blue but you dont need to use colours you could use items like hair bands sweat bands things like that hope i helped

Answer 3

If the twins were seperated and put into two different enviroments they would be differant because of the way they were raised and the food they had although they may still have the same characters.But if one was lacking in certain vitamins it could change their appearance same with weight.

Answer 4

I have mirror twins, these are identical but mirror image ie one os right handed and one left, when they look at photographs they are not sure who is who as they only ever see themselves in a mirror which means when looking at a photograph they see the sister as they see themselves in a mirror. as you know noones face is symettrical andf there are slight differences from each side so without being aware of those differences they identify themselves wrongly.

Answer 5

They dont. I am an identical twin - or was!  Once we got past our mid 20's we matured in different ways. We still look fairly similar but no more than that. We have never ate the same things, nor dressed the same. Both had different tastes in girls and went in different directions career wise. There is still a strong bond though.

Answer 6

well i have twin grandsons,17yrs. they are identical,but we can tell the difference,but teachers and other people can't they have different mannerism,and one is half an inch taller, they both eat o lot of the same food but there are a few differences, one doesn't certain foods, they both work at the same job,and when i was at the same dentist they visit the dentist said to me they both have exactly the same teeth, which is unusual for twins they do have a different set of teth but not these two, and one day i put them in different rooms my daughter sat with one, and i asked them to do things  like close one eye and put finger on one ear and do a happy smile and a sad smile. well out of ten things i asked them to do they were exact  on eight, and this only happens with x amount of twins.

Answer 7

I have two identical brothers and to everyone else they look the same but to me. Well I could tell them apart from the back of their heads or hands or even eyes. They look completely different to those they live with so are infact very different looking in the same way if you have two cats or dogs of the same breed which no one else can tell apart the owner will be able to see straight away

Answer 8

THEY ARE NEVER THE SAME! i have known 4 twins in my life  5 [if you count the non- identical ones] AND I HAVE ALWAYS FOUND ONE SOMETHING DIFFERENT i mean look at tom and bill kaulitz they are identical but anyone could tell the difference

Answer 9

Because identical twins have exactly they same DNA. This is because they came from one egg that split into two. You do get differences but these appear as they get older from different lifestyles and so on. If they eat different foods they will be different weights, ect.  

Answer 10

Identical twins are almost one person, a clone of each other.  They are extremely close in so many ways, in choice of fashions, hair styles, food, sports anything like that.

It has been found that where ID.Twins have been separated at an early age, they never-the-less continue in the manner described above, to do the same as each other.  It is quite uncanny.

Try some of these links in re. IS.Twins separated at birth etc.

http://www.google.com/search?sourceid=na...

Answer 11

I'm an identical twin, and we are very very similar. We're now 16, so I suppose things could still change. We like the same things, have the same sense of humor etc but still manage to stay far enough apart so we aren't joined at the hip.

EDIT - roxana A, I was the first born and was smaller than my sister, and even now she is half an inch taller than me.

Answer 12

The Kray twins were identical and they looked different as one was much bigger. One talked different too. One was also g*y and had mental problems but the other didn't.

You can see them on here

http://youtube.com/watch?v=D1Qc_8DoUCs

Answer 13

Identical twins are caused by ONE sperm cell fertilising ONE egg cell, and then the embryo splits completely into two new embryos. This causes identical twins because the DNA is exactly the same, it's been copied. Otherwise known as natural cloning.

However, non-identical twins are caused by two egg cells accidentally being released instead of one, and one sperm cell fertilising each egg cell. That's why they don't look identical, because they have different DNA.

So back to identical twins. Have you noticed that some identical twins don't look EXACTLY the same? One might have a *slightly* bigger nose, or something. This is because a person doesn't just get their looks from their DNA - it's partially environmental, too. The slightly bigger nose could be due to the way they were both growing inside their mother, one could have been squashed up slightly more than the other, for example.

Say one twin's favourite food was really fattening, and the other twin liked healthy food - (I know identical twins and they do not have the same taste in food, I don't know why this is but it happens) - this could cause them to look different as they grow older because they would have different lifestyles. Also, if they had different interests at school they may go on to get totally different jobs - one active, and one not active for example.

However, if the chance came to be that they both chose equally active interests and jobs and both watched what they ate they would probably stay looking identical for all of their life. Unless one chose to dye their hair, or became anorexic, etc.

And by the way, by "environmental changes" I mean things that happen after all of their genes have been chosen at fertilisation. eg if one gets a lack of oxygen at birth they would be smaller than the other twin, not due to genes but to the environment.

I hope I've shed some light on this situation. So now you see that although all of the identical twins *you've* seen have looked the same, sometimes they can be quite different depending on how they've lived their lives.

Answer 14

I think their bodies are almost the same.  Their metabolism is the same speed, their height is the same.  It's very unusal for one to like athletics and the other not to.  I think it's just that they do the same things so they end up being the same size.

Answer 15

OK, their basic features remain the same all their life like eyes, ears, nose, mouth, hair color, etc...Identical twins are IMPERFECT natural clones of each other.  Environmental factors can come in later on past babyhood, causing one to be heavier/thinner, and identical twins have different foot and finger prints.  Plus, identical twins can wear eye color contacts and dye, cut, and style their hair, so these are "environmental factors".  But identical twins can be different shades of skin, heavier/lighter, etc...Especially if one is raised somewhere else in the world.

Answer 16

Here'ss a bit of psychology for you - nature and nurture. Through nature they are incredibly similar, and they are brought up (nurtured) very similarly too. They're never exactly the same, I'm sure each one could point out the differences in the other, and often their similarities cause them to become opposites. There is often a leader of the two, a quieter on and a louder one that those close to them will pick up on. I child mind twins on occasion and there is a louder one, and a quieter one, one who will walk slowly with you and one who will rush off. These personalities have switched over time. I also know of a twin who's sister died (RIP), the one who died was the louder one but now the other is on her own she is louder. So I think they kind of reflect behaviours off of each other. Often they'll copy eachother too.  

Answer 17

Identical twins are clones, they share the xact same DNA, unlike non-identical twins who are mearly born at the same time.

Because they are clones they there will be no distinguishing differences, however as they are also 2 separate physical entities, over time they may develop differing charactersitics eg: if one loose a limb etc.

Answer 18

identical twins are a fertilised egg that has split in 2 so they have the same genes.  i think its been proved that even if they live separately they still do and like the same things its genetic.

Answer 19

How Identical Twins are Not Identical

There are two main factors that cause identical twins not to be truly identical:

Identical twins share the same DNA - but do not have identical DNA. When the egg splits into two halves to form identical twins, the DNA may not divide equally between the two cells. The basic concept is similar to when you cut an apple in half, the two halves may not look the same.

I don't want to get to complicated with the explanation, but DNA differences of identical twins revolve around the mitochondrial DNA (DNA that is not located in the nucleus of a cell).

Mitochondrial is DNA passed on to the child by Mom. A fertilized egg will have Mom's mitochondrial DNA, half of Mom's nuclear DNA, and half of Dad's nuclear DNA. When the fertilized egg splits into two, the twins will each have identical nuclear DNA, but not EXACTLY identical mitochondrial DNA. Physical differences in identical twins are contributed, in part, to how much and how similar the mitochondrial DNA each twin inherited from Mom expresses itself.

Environmental factors both prenatal (for instance, one twin having more room in the womb, viruses, genetic missteps, Twin-to-Twin Transfusion Syndrome, etc.) and after the babies are born (from something as minor as appetite to illness or accidents). Prenatal developmental differences can mean that one twin didn't quite "finish" a developmental stage that his or her twin did. For instance, an undescended testes is not uncommon in baby boys born early - about 50% of boys are born with an undescended t******e. In boy/boy twins it is not uncommon for one boy to have one or both testicles undescended, while his brother has both descended. It is also not uncommon for one twin to have no physical problems, and his or her twin having a heart or lung defect that is caused because the heart

Answer 20

identical twins, occur when a single egg is fertilized to form one zygote (monozygotic) which then divides into two separate embryos. Their traits and physical appearances are not exactly the same; although they have nearly identical DNA, environmental conditions both inside the womb and throughout their lives influence the switching on and off of various genes.

Answer 21

I'm an identical twin, and I will admit that my brother and I do look similar, but we are NOT the same, we share some interest like most siblings do, but we also have our own interest, and tastes! My parents made sure we were raised as individuals, which I can only thank them for!

Yes Genetically we are Identical, cell structure, everything, but we are in reality far from being identical. I have one other younger brother and I have as much in common with him as I do with my twin,

Answer 22

I was friends with identical twins and while they looked the same in some ways, there were a few obvious differences: the way they dressed, the shade of their hair (one dyed it, the other didn't), one was thinner than the other, one was lefhanded, the other righthanded...

You can't rule out genetics, but even identical twins are their own person and just because they're genetically identical, does not mean they like the same things. I really can't imagine the twins I knew to have worn the same clothes as each other in YEARS. Yes, genetically they have mainly the same build-up, but even with identical twins, if one cares about what he or she eats and excercises while the other sits on the coach all day eating fast food (just for example), you probably wouldn't even guess they're identical twins at all.

Look at Mary-Kate and Ashley Olsen: one had an eating disorder and became sickly thin while the other is more healthy, one's hair is darker blond while the other has a lighter colour (dyed?) and so on. If you think genetics mean EVERYTHING, you need a wake-up call.

Other than that, just because two siblings look alike A LOT doesn't mean they're twins either. If you took a picture of me as a baby and one of my kidsister at the same age, you wouldn't be able to tell us apart, but guess what - we aren't twins, she's actually 12 years younger than me.

Answer 23

Genetically, they're identical because they come from the same egg that split into 2 fetuses.

So they have the same physical bodies.

They can diverge, but it usually takes a pretty traumatic episode to cause it.

Answer 24

Being an identical twin, I can tell you that it has a lot to do with their up bringing, I was identical to my brother until he started taking medication that stunted his growth, and then I put on weight and we just get less and less identical as we grow up because of our life-style choices.

Answer 25

Interesting question.

I suppose it all comes back to the whole "nature vs nurture" debate.

How much of our personality is actually pre-determined by our DNA and how much is learned through the environment in which we live?

For example, if you got 2 twins and separated them at birth, then left one to grow up in a council estate, then took the other one to a well-off family in a different country, surely they would turn out to be different people and maybe even look different.

Answer 26

AMA explained it well. They have very similar if not identical DNA (same genetic structure; recieved the same genes/traits). Therefore, they usually have very similar interests and similar body structures. They have a similar brain which also makes them accept and value the same things and distinguish the same bad things. Also, they are raised in the same family where the parents feed them the same food and in the same portions. They are raised the same because the parents want the best for them and will try to do so for both, not just one of them.

Answer 27

They can get heavier or lighter; it depends on the environment that they grow up in. If they live apart, one may eat more than the other and gain weight, or one may get sick and lose weight. They are not always exactly the same appearance-wise.

They are identical in genetic make-up, however. Identical twins are natural clones, because they form when a fertilised egg splits in half.  

Answer 28

They're not always the same.

My brothers are identical twins- they were different heights, weights. When boxing one was a light weight, one a middle weight. One has eczema, the other had asthma. One ate veg, the other didn't. One had a seafood allergy, the other hasn't....

One is dead.

One is covered in scars.

Answer 29

Identical twins arise when "one" egg is fertilised and the resulting embryo then splits to become two embryos, they contain the same genetic information and so develop in the same way.

The same is not true for non-identical twins, in this case the ovaries release two eggs and both are fertilised and the pregnancy proceeds as normal only there are two embryos instead of one, both embryos have their own different genetic material, as was the case with myself and my sister.

Identical twins are "Genetically Identical" but this does not mean they will always look "exactly" the same, as they grow their environment, diet and physical activities will determine what they look like, for instance if one twin over eats they will put on weight, whereas if the other does not they will remain a healthy size. Many things determine what people look like not just genetic material.

The twins themselves are two completely different people with their own personalities, likes and dislikes, they do what they want, when they want, they are not linked, they just share the same genes and possibly some traits.

Answer 30

Some times they lose weight or gain it, but the reason why there is such a similarity is because just after consception the egg split into two having been fertilised by the one sperm.  Therefore each egg has exactly the same genes from the egg and the sperm.  They do often like the same food etc - studies have shown that identical twins separated at birth and then meet later on in life, despite their different upbringing have remarkably similar tastes, mannerisms etc.

Answer 31

Its to do with genes! Twins have identical DNA so their bodies react the same way to certain things.. and if they live in the same environment as each other then they will always be exactly the same.

But also they can look different, eg; You can't keep twins in the exact same environment! or feed them exactly the same.. so differences such as in height.. or weight occour.