microchimera

genetics

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Last updated

July 20, 2026

Quick Summary

In genetics, a chimera is an organism or tissue containing at least two different sets of DNA, often from fused zygotes. This differs from mosaics, which have genetically different cells from a single zygote, and hybrids, which have genetically identical cells from different species.

Microchimeras specifically occur when fetal stem cells or maternal cells transfer across the placenta, or through blood transfusions or organ transplants. The exact physiological role of microchimerism is not yet fully understood, though some research suggests potential links to immune responses and autoimmune disorders.1

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chimera
Human microchimeras are produced when fetal stem cells or maternal cells cross the placenta (fetal-maternal microchimerism) or following blood transfusion (transfusion-associated microchimerism) or organ transplantation. The physiological significance of microchimerism is poorly understood. For example, while there is some evidence that it may be associated with…
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Human microchimeras are produced when fetal stem cells or maternal cells cross the placenta (fetal-maternal microchimerism) or following blood transfusion (transfusion-associated microchimerism) or organ transplantation. The physiological significance of microchimerism is poorly understood. For example, while there is some evidence that it may be associated with…
Read More