roben (roben) wrote in i_am_a_twin,

Identical? Fraternal?

So, last night I got a book called Twins - An Uncanny Relationship? to a part in the second chapter where it explains the differences between identical and fraternal twins. I was like, well I'm identical... "They grow into two seperate foetuses, each with its own placenta, which are 'fraternal' or 'non-identical' twins; the scientific name for them is dizygotic from the Greek for 'two eggs'." Friday Mom and I were watching Nine Months, and it was at the end where the birthing scene was, and she was all screaming and in a lot of pain, and I asked mom, is it really like that, do you really do that much screaming? and she was like, Uh.. yeah, that's not made up. My mom had my sister and I natural. NO EPIDURAL. In fact, if you didn't know this, she also didn't know that there was two of us. It was the eighties and her doctor didn't think Ultrasounds were necessary/safe... Needless to say, afterwards he always did ultrasounds. I was the first born. So I asked, could you feel Julie still in there after you had me? She said, "No. But apparently the doctor could. After Julie was born both placentas came out." So does this mean I'm fraternal? After all these years? Here's what I've found out.

I found a 'mom and pop' website to fill me in on what they knew of Mirror Image Twins.

" If you are mirror image twins it means that you are also identical twins. Mirror image twins are created when the fertilised egg splits quite late (around days 9-12), any later and twins can be co-joined.

Mirror Image twins have small mirror image differences but are actually genetically identical; this means you have the exact same DNA!

Some parts of the body can be mirrored; but not the appendix or heart or other internal organs as far as we know. We have some examples of our own mirroring:

* We are opposite handed (Flame is left and Lake right)
* We tend to have mirror image dental problems
* Our cowlicks (tuft of hair at fringe) are on opposite sides
* Where people often have different size feet, with us the opposite foot is larger
* We look very similar to each other but the resemblance is even stronger if we stand facing each other (as though in a mirror) rather than side by side. Or get both of us facing into a mirror and things all start to look very confusing.
* Our finger prints don't seem to conform to being mirror image – instead they are nearly identical (only one pair of fingers has any major difference)

We've had emails from many other mirror image twins who tell us they also have these types of physical similarities. We don't really seem to experience mirror image aptitudes and have instead have very similar interests and skill levels."

Julie and I are mirror image twins, Here are our mirroring... quite like the ones mentioned above...

* I'm a righty shes a lefty
* In Orthodontics we had the same crowding problem on opposite sides
* We both of a mole on our foot in the same place on opposite feet
* We part our hair on opposite sides (not a genetic thing, but I'm pretty sure it was unintentional)
* Both have opposite dimples in cheeks - mines on the right heres on the left
* Same vision, opposite eyes. (Before I got lasik)

We also have similar interests and skill levels. (both in Art)

But what about the placenta? Do mirror image identical twins get there own placenta?

Wikipedia told me this, which only confuses me more.

"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 identical DNA, environmental conditions both inside the womb and throughout their lives influence the switching on and off of various genes. Division of the zygote into two embryos is not considered to be a hereditary trait, but rather an anomaly that occurs in birthing at a rate of about 3 in every 1000 deliveries worldwide,[3] regardless of ethnic background. The two embryos develop into fetuses sharing the same womb. When one egg is fertilized by one sperm cell, and then divides and separates, two identical cells will result. If the zygote splits very early (in the first 2 days after fertilization) they may develop separate placentas (chorion) and separate sacs (amnion). These are called dichorionic, diamniotic (or "di/di") twins, which occurs 20-30% of the time. Most of the time in identical twins the zygote will split after 2 days, resulting in a shared placenta, but two separate sacs. These are called monochorionic, diamniotic ("mono/di") twins.

In about 1% of identical twins the splitting occurs late enough to result in both a shared placenta and a shared sac called; monochorionic, monoamniotic ("mono/mono") twins. Finally, the zygote may split extremely late, resulting in conjoined twins. Mortality is highest for conjoined twins due to the many complications resulting from shared organs. Mono/mono twins have an overall in-utero mortality of about 60%, principally due to cord entanglement prior to 32 weeks gestation. Many times, monoamniotic twins are delivered at 32 weeks electively for the safety of the babies. In higher order multiples, there can sometimes be a combination of fraternal/identical twins."

The Crimson Twins are mirrors. lol.
"They are mirror images of each other; Tomax's hair is parted on the right side of his head and Xamot's on the left, the piping on their uniforms goes up the opposite side on each twin, and even their names are mirror images of one another—with Xamot reading as Tomax in a mirror. The only distinguishing mark between the two is a scar on Xamot's right cheek, which Tomax does not have. Tomax and Xamot share an empathic connection commonly known as "The Corsican Syndrome" in which identical twins are believed to be psychically bonded, as per The Corsican Brothers. While this is often useful, as it allows them to communicate wordlessly and finish each others sentences, it is also a liability as they feel each other's pain."

"Mirror-image twins occur only in identical twins. In approximately 23 percent of identical twins, the fertilized egg splits later than 7 days following conception.

The original right half of the egg becomes one twin and the original left half becomes the other. These twins will often have "mirror images" of their features, such as hair whorls that run clockwise in one and counter-clockwise in the other, a birthmark on the right shoulder of one and the left shoulder of the other, etc. There is no specific test for determining if twins are mirror-image, however. The determination is made by observation only, and the twins must be mono-zygotic, or identical.

This may be a partial explanation for the fact that a little over one third of identical twins are left-handed, double the rate in the general population. In extreme cases, all of the internal organs are reversed in one of the twins, with the heart on the right, the liver on the left, and the appendix on the left."

Well, I'm going to conclude that Julie and I are a rare case of splitting later than normal - and still developing our own placentas - identical twins.

x-posted in i_am_a_twin
  • Post a new comment


    Comments allowed for members only

    Anonymous comments are disabled in this journal

    default userpic
  • 1 comment