Mosaicism is a genetic condition where an individual has two or more different cell lines that originate from a single fertilized egg. This means that some cells may have a different genetic makeup than others, leading to variations in traits or health conditions. Mosaicism can occur in any organism, including humans, and can affect various tissues and organs. In humans, mosaicism can result from errors during cell division in early development. It can lead to a range of outcomes, from no noticeable effects to specific disorders, such as Down syndrome or Turner syndrome. The severity and type of symptoms depend on the proportion and distribution of the different cell types.