Topic summary
Chimerism

Extracted from the Wikipedia article Chimera (genetics).
In marine sponges
Chimerism has been found in some species of marine sponges. Four distinct genotypes have been found in a single individual, and there is potential for even greater genetic heterogeneity. Each genotype functions independently in terms of reproduction, but the different intra-organism genotypes behave as a single large individual in terms of ecological responses like growth.