Presumptive evidence for the absence of functional germ cell chimerism in the marmoset.

Presumptive evidence for functional germ cell chimerism in the marmoset was evaluted by calculating the offspring sex ratio of young derived from animals in which the blood chimerism status was known. In the four possible mating combinations involving chimeric and non-chimeric marmosets, there was no apparent deviation from the anticipated 1:1 sex ratio. Analysis of 2,500 primary spermatocytes from ten known blood chimeras failed to reveal a single cell in which an unequivocal XX bivalent could be identified. The combined breeding and cytogenetic data offer presumptive evidence against functional germ cell chimerism in the marmoset.