What is cell autonomy?
A genetic trait in multicellular organisms in which only genotypically mutant cells exhibit the mutant phenotype. eg. a transcription factor is usually cell autonomous.
Conversely, a cell non-autonomous trait is one in which genotypically mutant cells can be rescued to wildtype phenotype by neighbouring genotypically wildtype cells. eg. A signalling factor will often have non-autonomous effects.
There is also the very rare case of domineering non-autonomy in which genotypically mutant cells cause other cells (regardless of their genotype) to exhibit a mutant phenotype. eg. in types of polarity, where a mutant cell sends an incorrect polarity signal to the neighboring wildtype cell.