Developmental interactions of cells mutant for Strong's luxoid gene with normal cells in chimeric mice

Mouse chimeras were made by fusing embryos from the albino BALB/cFo normal skeleton strain producing a slow variant isozyme of glucose phosphate isomerase (GPI) with embryos from the black pigmented SH strain carrying Strong's luxoid gene (symbol: 1st) for skeletal anomalies and producing a fast GPI variant. All chimeras were estimated to bALB/cFo mice to determine the mosaic status of their gonads. In addition, the quantitative proportions of BALB/cFo and SH cells in skin and limb muscles of chimeras were determined by visual estimation of the degree of coat pigmentation and by a serial dilution method applied to electrophoresis and GPI isozyme reaction of limb muscle homogenates. Skeletons of all chimeras and of representative samples of BALB/cFo and SH mice were examined and graded for expression of a number of normal and mutant skeletal characteristics. The most important conclusion of this study is that there was a definite quantitative effect on the development of skeletal characteristics exerted by the relative amount of BALB/ cFo and SH cells present in a chimera such that a structure could vary from normal to entirely mutant, depending on the proportion of each type of cell present.