In Italian a Chimera is a foolish fantasy, something unreal (a bit like the animal I suppose)
In genetics a Chimera is an animal that has two or more different populations of genetically distinct cells that originated in different zygotes.
In vitro, embryos of a species are mixed with cells of another species to create an animal composed of different parts...
Sounds difficult?
Let's make it clearer...
Imagine a mother discovered one day that one of her two children was genetically not hers.
Suddenly the question becomes not “Who?” but rather “Huh?”
It's almost unheard of and yet it does happen... The mother is a human Chimera
The most common form of human chimera is called a blood chimera. This happens when fraternal twins share some portion of the same placenta. Each twin is genetically separate except for their blood, which has two distinct sets of genes, and even two distinct blood types.
What happened to "the mother" is a much rarer occurrence. Rather than a simple exchange of blood, "the mother and her fraternal twin" merged in utero, leaving only one fetus. The cells in her body are a mosaic of genes from both of the original embryos.
After a bit of research I found out that doctors at the University of Edinburgh in 1998 had a patient referred to them for an undescended left testicle. However, when they examined him they could not find a second one. Instead they found something unexpected, an ovary and a fallopian tube. This patient was a chimera formed from the fusion of male and female embryos.
And I thought I had it all figured out! ...
3 comments:
I have also heard of genetic chimeras where an individual has only some cells of the body affected by a particular genetic mutation. The example I heard of was a woman with Turners syndrome, who had the full complement of chromosomes in some cells but one X missing in others. I guess it must be caused by the mutation occuring partway through feotal development.
That is so very interesting...
So much to still learn :-)))
May not be a chimera issue, have a sister-in-law, born, of course a female, fully formed, however with testicals up inside her body (no ovaries), however she is definently a woman by all other means. Appears to be an annomoly in family history. Can this be explained on this website, or can I be referred to another website?
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