Semi-Identical twins discovered

[Polly]

Weird.

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

[Jenny]

verrry interesting. I wonder how many more twins out there are semi-identical, but assumed to be identical.

[Sarah]

That's strange. I had always thought that if an egg was fertilized by two sperm, it wouldn't be viable. I can't remember where I read that though, so it could be (and probably is, if there are semi-identical twins) false.

[Marzipan]

I'm not really sure why they're using the term "semi-identical." They do not share identical DNA. Hence, not identical and semi-identical just smacks of jargon. Sure, the method of fertilization is interestingly between that of fraternal and identical twins, but the terminology is just sort of annoying. Al humans have DNA that is 99% identical. It's only .1% of our DNA that enables us to differentiate between, say, OJ Simpson and the "real killer." ;)

[wendygrace]

Sarah, I do believe that is what we were taught in biology class. I suspect that this is rare and probably results in miscarriage more often then not. I suspect that it is likely that this type of fertilization may have caused that child's issues.