For a moment I thought the claim was Calment was a chimera as well as a long-lived person. A chimera is essentially a single organism that's made up of cells f

For a moment I thought the claim was Calment was a chimera as well as a long-lived person. A chimera is essentially a single organism that's made up of cells from two or more "individuals"—that is, it contains two sets of DNA, with the code to make two separate organisms. One way that chimeras can happen naturally in humans is that a fetus can absorb its twin. This can occur with fraternal twins, if one embryo dies very early in pregnancy, and some of its cells are "absorbed" by the other twin. The remaining fetus will have two sets of cells, its own original set, plus the one from its twin. https://www.scientificamerican.com/article/3-human-chimeras-that-already-exist/ https://www.scientificamerican.com/article/3-human-chimeras-... Unfortunately the claim is more like identity theft. Much less interesting biologically. This article outlines four types of known human chimeras: https://www.healthline.com/health/chimerism https://www.healthline.com/health/chimerism