Figure 3From: Using mouse models to study function of transcriptional factors in T cell development Stages in T cell development. Early T cell precursors (ETPs) differentiate from double negative (DN) to double positive (DP) to single positive (SP) stages. Arrows indicate cell differentiation. Note that ETP and DN2 thymocytes contain non-T-cell options. β- and γδ- selection occurs during the accumulation of the DN3 T cells.Back to article page