Presence of tear-drop poikilocytes in the blood of 18-month-old GATA-1^low mice.

May-Grünwald-Giemsa staining of representative blood smears obtained from GATA-1^low mice at 6 months (upper panel, as negative control) and 18 months (lower panel) of age. Open arrows indicate the dismorphic platelets characteristic of the blood of the Gata-1^low mice.18 21 Solid arrows indicate the tear-drop poikilocytes that circulated in the blood from these mutants since 15 months of age. Similar results were observed in blood smears from at least 4 to 6 mice. In particular, 18 mice were analyzed in the 12- to 18-month age group. (Original magnification, × 100).