Cellular competition in the development of ocular tissues in allophenic mice

C57BL/6 mice exhibit impaired lens development as evidenced by competition studies with allophenic (chimeric) mice. Strain-specific differences in electrophoretic forms of glucose phosphate isomerase were exploited to determine the strain composition of various ocular and nonocular tissues in allophenic mice constructed from C57BL/6 and DBA/2 strains. As expected, there was variation from one animal to the next in overall mosaic composition, as well as variation among most ocular and nonocular tissues within individual animals. In contrast, when individual lenses from the same animals were assayed there was a marked and consistent deficiency of the C57BL/6 component. Control experiments indicated that these results are not the consequence of peculiarities of marker enzyme expression in the lens. Since lens formation occurs early in embryogenesis any anomaly at this stage could influence the normal induction of later ocular structures. We believe that the impaired lens-forming capacity of C57BL/6 mice may be the underlying cause of the 5-10% frequency of overt ocular defects in this strain.