Fine Structure of Cells in Embryos Chimeric for Mutant Genes at the T/t Locus

Abstract

Since it has been proposed that at least some of the abnormalities in mouse embryos that are homozygous for lethal mutations at the T/t locus are interpretable as due to derangements of cell recognition and response (Bennett 1975), we thought that we might be able to look directly at the affected cells in embryos chimeric for the mutant and wild-type genotypes during the appropriate developmental stages in order to see what kinds of cellular associations occur when cells of the defective type are in proximity to their normal counterparts. Such observations might give a clue to the kind of deficiency, in a mechanical sense perhaps, that is involved in the mutant embryo. In short, do cells of the mutant phenotype remain unchanged, or do they react to the new environment and participate in normal development? With respect to the T/t locus, this question has been approached once before, in 1964 by Mintz for the t12 gene.