Could someone explain the twins and the genes?

Question

Someone told me that her father's skin is lemon yellow, that he has black (or very close to) eyed and hair and that her mother's skin is greyish-olive and that her hair colour is closed to her skin's colour (somekind of blonde). My girlfriend is dark orange brown. She thinks she might have been adopted and that she might have two twin sisters. She had somekind of dream or blackflash where she saw the yellow guy and olive woman. She find them looking like her, just as she found two other girls looking like her (she thinks they might be her twin sisters). She says she has a twin sister who is white-yellowish with hair colour close to her skin colour (somekind of golden blonde), with black-brownish eye colour and with her mother's face shape; and another twin sister who has red hair, beige white skin with blue eyes and her father's face shape. Was my girlfriend having dreams or blackflash? Have there ever been such type of twins? If so, does it run in the family?

I'm not asking for any comparison. One of the thing I was wondering is: have there be any proof that identical twins could present themselves differently (skin colour, physical shape, eye colour,...).

Another thing I was wondering is: have there ever been any proof that fraternal twins could share the same bond as identical twins share (for example: one is pregnant and the other one has her pregnancy symptoms or see her breast enlarged,...).

But there are other things that make me wonder and may be that's why my question could seem unclear (you might answer to what you think you understood through my question).

Answer 1

That's kind of a confusing question. What exactly are you asking us to compare? General appearance? I don't know what you mean by "type of twins."

There are two types of twins: fraternal and identical. Identical twins arise when one sperm enters one egg, and the egg splits in half early in differentiation, so that two embryos with the same DNA are formed. Same DNA = they look the same. These twins are the same gender.

Fraternal twins occur when two different eggs in the mother's womb are fertilized by two different sperm. In this case, the twins look just as alike each other as any regular siblings would. They don't have to be of the same gender.

You can also have triplets with a combination of the above. The mother can have two eggs; one egg is fertilized and develops normally, while the other egg is split to become identical twins.

As far as I've heard, there's no genetic tendency to have twins - that is, it shouldn't run in the family.

Sorry if I haven't addressed your question well, but I really didn't understand it.

Answer 2

The characteristics you mention are controlled by more than one pair of genes each (polygenic traits). It's very complicated to unravel inheritance of these traits.

As far as dreams or "backflash" ... I don't think there's a proven way to find out which it was. Dreams can seem very real, and it's also true that we sometimes have flashes of memory. For that matter, sometimes we have flashes of false memory if we have imagined a thing to have happened and thought of it enough times.

Interesting dilemma, though.