Chimera develop from one single fertilized egg. Mosaic originate from different zygotes.

Identical twins will not necessarily have same blood group type. Chimeric twins will usually have the same type of blood group.

A chimeric person can have two sets of blood type.

Fraternal twins has their own placenta but they share the same blood supply through the mother’s womb.

microchimerism is a condition in which small fractions of the cells are different.

In vitro fertilization (IVF) may contribute to the number of human chimeras.

Artificial chimera can occur through transfusion of second cell lines via experimental engineering.

Chimerism does not have external signs and symptoms.

In dispermic chimeras, two eggs that have been fertilized by two sperm fuse together, producing a so-called tetragametic individual—an individual originating from four gametes, or sex cells.

A twin chimerism can occur is due to blood vessel anastomoses in the placenta, through which one twin can transfuse blood cells, including stem cells, and also primordial germ cells to the other and vice-versa.