The Reese laboratory is defining the organizing principles and developmental mechanisms governing the formation of the retinal architecture. Various projects are examining the transformation of an undifferentiated retinal neuroepithelium into the mature structure, including the clonal expansion of retinal progenitors, the migratory behavior of distinct types of newborn retinal neuroblasts, the pattern formation in retinal mosaics, dendritic differentiation and establishment of connectivity within the developing plexiform layers, and the control of naturally occurring cell death. Recombinant inbred strains of mice and quantitative trait locus (QTL) analysis are used to identify causal genes and their sequence variants modulating the demographic properties that characterize the various types of retinal cell populations.