There is a natual chimerism present in every woman's body.
Early in foetal development every cell has to decide for itself which X-chromosome it will use. Once that decision is made it sticks everytime the cell divides. So you get clumps/stripes of cells that share the same x-chromosome next to stripes/clumps that have the other chromosome active.
Early in foetal development every cell has to decide for itself which X-chromosome it will use. Once that decision is made it sticks everytime the cell divides. So you get clumps/stripes of cells that share the same x-chromosome next to stripes/clumps that have the other chromosome active.