Semi-identical twins, did anyone else see this?

Question

http://news.yahoo.com/s/livescience/20070326/sc_livescience/raresemiidenticaltwinsdiscovered

This just boggles my mind, its very interesting.

Answer 1

It's really interesting, but the news story about it is crap. I had to look up the original journal article because the news story mentioned that one of the twins was a true hermaphrodite, but didn't say anything more about it. Well, a true hermaphrodite has both male and female DNA, so that obviously complicates things. It turns out that what the study actually found was that both twins are chimeric, which means that they have two sets of DNA, and the interesting thing is that the two sets of DNA have separate contributes from the father but a single contribution from the mother. So like the article said, one egg and two sperm make two babies, but where the story is misleading is that both sperm ended up in both babies. The two sets of cells in both babies are semi-identical, but a tissue sample from either baby has both sets of DNA in it (provided it's a big enough tissue sample to get some of each type of cell).

Normally, chimeras form essentially when two separate fertilized eggs that would normally make fraternal twins fuse early in development and make a single baby that ends up with a mix of tissues from each egg. Most of the time it goes totally unnoticed, and only shows up either if the two eggs have different genetic genders and the baby ends up with a mix of male and female gonads, or if it happens to be picked up on a genetic test that's done for other reasons (ex. paternity tests). But with the babies in that story, they at some point had two sets of DNA that could potentially have formed separate semi-identical twins just like what happens with fraternal twins, except that they either never completely separated, or else separated and then got mixed together and, they ended up making two babies that both have both types of cells.

Answer 2

Thanks for the info and website address on this subject! It was quite interesting but I think there will be much more of these kinds of developments in the future.

With all the infertility doctors out there treating women with drugs, etc. and the scientific advancement with respect to cloning .... who knows what we will be seeing in humans about 50 years from now!

Sometimes I wonder if science hasn't gone a bit too far. It can all get a bit scary ... but I suppose if you're a youngster today and grow up with all this advancement being considered normal .... it just becomes a part of everyday life!

Thanks again for sharing ...

Answer 3

Very interesting. I've never heard of that. Usually once the egg has been fertilized it creates a hard outer shell to prevent any other sperm from entering. Must be extremely rare.

Answer 4

Wow, neat! Did you know Mary Kate & Ashley olson are NOT identical twins? Sometimes twins can just look alike even if they aren't identical!

Answer 5

i have a set of twins, and actually, to me they are semi-identical. they were fraternal, but they share none of the same features. they are actually two seperate kids, just born at the same time. Both are girls, but i was told orginally that the second twin was a boy. the dtr swore he saw testicles, which i know that some babies can develop testicles and then they can re-tract or just be born with both organs (although mine wasnt).

Answer 6

it might desire to purely be possible. have you ever extra this as much as the persons around you who ask questions approximately them being same or their well being care provider? you're their mom and additionally you already know them extra ideal than anybody else!

Answer 7

Thats crazy.

thanks for sharin this

Answer 8

wow creepy

Answer 9

weird

Answer 10

I just saw it too...

Pretty neat :-)