Agile Tortoise
Greg Pierce’s blog
Chimeras
NPR had an interesting piece this morning on Chimera twins (Audio)…a phenomenon that I had not heard of. Apparently, sometimes two fertilized eggs, that would normally be destined to become fraternal twins, can merge very early in the process and produce a single child — with two people’s DNA.
In the piece, they spoke with a 60 year old woman who is a chimera. This was discovered after she was in need of a kidney transplant, and testing of her three children indicated they were not her children. Ultimately, after a lot of testing, doctors realized that she had two distinct sets of genes, ie, the DNA in her blood was different than that in her thyroid, bladder and many other organs. It so happens she passed along the genes that were not in her blood to her children.
They were saying that more and more chimera’s are being discovered worldwide since the advent of widespread DNA testing — but that it’s not clear how many are really out there…and it potentially raises a lot of questions about the validity of DNA testing in some situations. Very interesting stuff.
