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Yes, sometimes called "mosaic" or "chimera", depending on how it happened. Basically, the organism is made up of cells that aren't genetically identical. In mosaics, it's usually that there was an error in cell division after the egg was fertilized, and the cells with the error just copied that error to all the cells that descended from the original. I once described the analogy of having a one-page document, then photocopying it (like cell division). Then take one copy and draw an X on it. Continue making one copy of each piece of paper, and each copy of that one marked with an X (or copy of a copy, etc) will also have that X. That's what a mosaic is. How early the mistake happened will affect how many copies have the mistake.
Chimeras are something different. What happens is that two different fertilized eggs fuse, then continue to grow into one fetus. The resulting organism has some cells from one fertilized egg, and some cells from the other fertilized egg. It's one organism that's a mix of cells from fraternal twins. I remember a documentary on television about two women who were discovered to have this condition. In one case, a woman had a child, and when that child had a test for something unrelated, it was discovered that she couldn't be the biological mother because the DNA test failed. They later checked her other child and found the same result. Because she was on public assistance at the time, she was taken to court for running some kind of scam. She really did get pregnant and give birth to these children, and it wasn't until she had her next child (she was pregnant at the time) and they ran the test again on the new baby (and again it showed that she couldn't be the biological mother based on a DNA test) that they looked further. It seems she was a chimera, and the cells that made up her reproductive organs had a different set of chromosomes (essentially, they arose from cells from her fraternal sister, whom she absorbed in utero) than the rest of her body (her DNA was sampled from blood, not reproductive tissue). The second story in the documentary occurred when a woman was tested for organ donation for one of her children, and they found similar results from DNA tests. Had these incidents not happened, these two women would never have known that they were chimeras.
Pretty weird, huh?
Yes, sometimes called "mosaic" or "chimera", depending on how it happened. Basically, the organism is made up of cells that aren't genetically identical. In mosaics, it's usually that there was an error in cell division after the egg was fertilized, and the cells with the error just copied that error to all the cells that descended from the original. I once described the analogy of having a one-page document, then photocopying it (like cell division). Then take one copy and draw an X on it. Continue making one copy of each piece of paper, and each copy of that one marked with an X (or copy of a copy, etc) will also have that X. That's what a mosaic is. How early the mistake happened will affect how many copies have the mistake.
Chimeras are something different. What happens is that two different fertilized eggs fuse, then continue to grow into one fetus. The resulting organism has some cells from one fertilized egg, and some cells from the other fertilized egg. It's one organism that's a mix of cells from fraternal twins. I remember a documentary on television about two women who were discovered to have this condition. In one case, a woman had a child, and when that child had a test for something unrelated, it was discovered that she couldn't be the biological mother because the DNA test failed. They later checked her other child and found the same result. Because she was on public assistance at the time, she was taken to court for running some kind of scam. She really did get pregnant and give birth to these children, and it wasn't until she had her next child (she was pregnant at the time) and they ran the test again on the new baby (and again it showed that she couldn't be the biological mother based on a DNA test) that they looked further. It seems she was a chimera, and the cells that made up her reproductive organs had a different set of chromosomes (essentially, they arose from cells from her fraternal sister, whom she absorbed in utero) than the rest of her body (her DNA was sampled from blood, not reproductive tissue). The second story in the documentary occurred when a woman was tested for organ donation for one of her children, and they found similar results from DNA tests. Had these incidents not happened, these two women would never have known that they were chimeras.
Pretty weird, huh?
