FIG. 4.

Emergence of clonal populations in SCL LMO1 transgenic mice. (A) Total thymocytes from 4-week-old mice analyzed by Southern blot hybridization to a TCR Cβ2 probe. Genotypes are as indicated, and size standards are in kilobases. Some but not all of the SCL LMO1 mice in this experiment show discrete rearranged fragments, reflecting marked clonal expansion. (B) The clonal populations become more pronounced with age. Total thymocytes from mice at 4, 8, or 12 weeks of age were analyzed by Southern blot hybridization to a TCR Cβ2 probe. Increasing prominence of one or several clonal rearranged fragments is seen at 8 and 12 weeks compared to 4 weeks.