FIGURE 1.

(A) Overview illustrating the experimental approaches to document the development of hematologic malignancies. (A) Scheme documenting the different types of analysis performed to investigate the presence of hematologic malignancies. Genotyping is performed on the blood and the dissected thymus by PCR amplification of the CRISPR/Cas9 targeted regions followed by deep sequencing of the PCR fragments and analysis of the INDEL signatures (left). Phenotyping is done by manual counting of the blood cells or by flow cytometry. In addition, lymphoid organs such as the thymus, and spleen are subjected to immunohistological analysis and transcriptomic profiling. Other organs like the kidneys and the liver are evaluated for the presence of proliferating and disseminating lymphoblasts (right). (B) Timing of the analyses that can be performed for assessing the presence of leukemic disease and to evaluate disease progression. Legend: “++,” “+” and “–” refer to straightforward, difficult and impossible to nearly impossible to perform, respectively. Analysis can be impossible to do due to (a) immature cells jeopardizing cell discrimination, (b) too low input of thymocytes for flow cytometry in early stage tadpoles, (c) shrinking of thymi in older animals, which impedes successful dissection, (d) aberrant scattering in immature cells, (e) extremely small size of the spleen in early stage tadpoles, which therefore is difficult to dissect. Drawings adopted from Xenbase (http://www.xenbase.org/anatomy/alldev.do).