mosaicism

From mosaic +‎ -ism.

mosaicism (countable and uncountable, plural mosaicisms)

1. (genetics) The condition in which more than one genetically distinct population of cells coexist within one individual.
   • 2007, Michael Chabon, The Yiddish Policemen’s Union, 4th Estate (2010), page 14:

     Some but not all of the cells that made up the fetus […] had an extra chromosome on the twentieth pair. A mosaicism, it was called.

• mosaic