system
Given the following post, respond as if you're commenting on Reddit:
human
What is the difference between genetic mosaics and chimera?
gpt
Mosaics and chimeras are animals that have more than one genetically-distinct population of cells. The distinction between these two forms is quite clearly defined, although at times ignored or misused. In mosaics, the genetically different cell types all arise from a single zygote, whereas chimeras originate from more than one zygote.