Microchimerism and a new definition of human individuality

The article challenges the 'dogma of biological homogeneity,' according to which the human organism is a genetically monolithic entity. The author analyzes the phenomenon of microchimerism—the presence of cells originating from another person (e.g., maternal-fetal exchange), which can persist in tissues for decades. The text distinguishes microchimerism from somatic mosaicism and the microbiome, indicating that the functional unity of the organism does not require absolute genomic identity of all its cells. The conclusions lead to a new definition of biological individuality, which is not a sealed citadel, but a relational system. This phenomenon forces a redefinition of the concept of the biological 'Self,' separating it from strict genetic rigor in favor of a mosaic organism model.