Chimera
Human chimeras were once thought to be so rare as to be just a curiosity.
But there's a little bit of someone else in all of us, says Claire
Ainsworth, and sometimes much more...
EXPLAIN this. You are a doctor and one of your patients, a 52-year- old woman, comes to see you, very upset. Tests have revealed something unbelievable about two of her three grown-up sons. Although she conceived them naturally with her husband, who is definitely their father, the tests say she isn't their biological mother.
Somehow she has given birth to somebody else's children.
This isn't a trick question - it's a genuine case that Margot Kruskall, a doctor at the Beth Israel Deaconess Medical Center in Boston,
Massachusetts, was faced with five years ago. The patient, who we will call Jane, needed a kidney transplant, and so her family underwent blood tests to see if any of them would make a suitable donor. When the results came back, Jane was hoping for good news.
Instead she received a hammer blow. The letter told her outright that two of her three sons could not be hers. What was going on?
It took Kruskall and her team two years to crack the riddle. In the end they discovered that Jane is a chimera, a mixture of two individuals - non-identical twin sisters - who fused in the womb and grew into a single body. Some parts of her are derived from one twin, others from the other.
It seems bizarre that this can happen at all, but Jane's is not an isolated case. Around 30 similar instances of chimerism have been reported, and there are probably many more out there who will never discover their unusual origins.
While cases like Jane's are the extreme, researchers now think that there's a little bit of chimera in all of us, and what was once seen as a biological oddity may serve a vital function. We may owe our lives to being chimeras.
At first, Jane's case had Kruskall completely puzzled. The original data came from the tests done to "tissue-type"
But there's a little bit of someone else in all of us, says Claire
Ainsworth, and sometimes much more...
EXPLAIN this. You are a doctor and one of your patients, a 52-year- old woman, comes to see you, very upset. Tests have revealed something unbelievable about two of her three grown-up sons. Although she conceived them naturally with her husband, who is definitely their father, the tests say she isn't their biological mother.
Somehow she has given birth to somebody else's children.
This isn't a trick question - it's a genuine case that Margot Kruskall, a doctor at the Beth Israel Deaconess Medical Center in Boston,
Massachusetts, was faced with five years ago. The patient, who we will call Jane, needed a kidney transplant, and so her family underwent blood tests to see if any of them would make a suitable donor. When the results came back, Jane was hoping for good news.
Instead she received a hammer blow. The letter told her outright that two of her three sons could not be hers. What was going on?
It took Kruskall and her team two years to crack the riddle. In the end they discovered that Jane is a chimera, a mixture of two individuals - non-identical twin sisters - who fused in the womb and grew into a single body. Some parts of her are derived from one twin, others from the other.
It seems bizarre that this can happen at all, but Jane's is not an isolated case. Around 30 similar instances of chimerism have been reported, and there are probably many more out there who will never discover their unusual origins.
While cases like Jane's are the extreme, researchers now think that there's a little bit of chimera in all of us, and what was once seen as a biological oddity may serve a vital function. We may owe our lives to being chimeras.
At first, Jane's case had Kruskall completely puzzled. The original data came from the tests done to "tissue-type"