Fascinating.
Two very interesting things have come to my attention lately.
The first is that SOMETIMES, but VERY, VERY, VERY RARELY the males sperm contributes mitochondria to the egg. It is usually destroyed almost immediately, but even more rare than it enters, occasionally it survives.
The most interesting thing by far is that they were getting ready to do brain surgery on some gal. She was the mother of three kids, IIRC, two of them daughters.
While typing her genetics before the test, they found some genes that shouldn’t a been there.
They matched the genotype to one of the daughters.
Seems that sometimes during pregnancy, the fetal cells can cross the placenta and get into the mothers bloodstream. The mothers immune system is somewhat tuned down during pregnancy so she doesn’t go into full scale immune rejection of the fetus.
The babies cells then established themselves in the mothers brain and everybody was hunky dory with it!
Amazing!
AFAIK, it’s been confirmed with a couple other cases.
Sounds like a chimera - their bodies contain the DNA of two individuals.
This is caused by two zygotes combining, in the womb, into one and developing as a single foetus. The two zygotes should have been fraternal twins.