To explore the possible influence of defined genetic backgrounds on photoreceptor viability and function in mice carrying a targeted disruption of the rhodopsin gene, the severities of retinopathies in Rho-/- mice on C57BL/6J and 129Sv congenic backgrounds were compared by light microscopy and electroretinography and qualitatively by in situ end labeling of DNA in apoptotic photoreceptor nuclei of retinal sections. Cone photoreceptor viability and function were shown to deteriorate more slowly on the C57BL/6J background in comparison to that of the 129Sv, with significantly greater numbers of outer nuclear layer nuclei in the retinas of C57BL/6J mice at 3 and 4 months of age. Both amplitude and waveform features of the ERG were shown to be remarkably different in the two strains, indicating an approximately 6-fold difference in C57BL/6J Rho-/- mice compared to 129Sv Rho-/- mice at 80 days. Thus, in comparison with the 129Sv strain, genetic modifiers appear to constitute a component of the C57BL/6J background, the expression of which significantly protects cone photoreceptors from apoptotic death in a mutation-induced murine retinopathy. The differences in phenotype revealed in this study are sufficient in principle to provide a basis for comparisons to be made between QTLs in light-induced and mutation-induced systems.

What does church membership mean for women? Texts like Galatians 3:27-28 imply equality; experience contradicts this. Underlying the controversy are assumptions about women's nature as women. Baptismal practice suggests women's equality but experience denies it. Part I examines experience: in lay ministry, in marriage, and as economically marginalized. Turning from experience to theoretical analysis, there are two answers to the question of women's nature: women are inferior, or women are equal. Part II studies the two models at work in the dialogue held between representatives of the Women's Ordination Conference and the U.S. National Conference of Catholic Bishops as participants addressed the question: “What is woman?” Finally the two models are operative in the testimony given in the national hearings for the bishops' pastoral on women. Part III analyzes the reports of the national hearings, uncovering the correlation between model, methodology, and whether a group's feminism leads it to social or issue critique.