Differential gene expression in JAK2V617F MKs. MKs from 4 control and 4 JAK2V617F mice were cultured and purified through a BSA gradient. RNA was extracted, and expression arrays performed. (A) Hierarchical clustering of control and JAK2V617F gene expression values separates the samples into 2 different populations. Shown above each cluster are the corresponding approximately unbiased and bootstrap probability values, which indicate the strength by which the cluster is supported by the data. (B) Genes that were over- or underexpressed by a factor of 1.25 with P < .05 and false discovery rate <0.25 are presented in the table. * denotes average signal for all 4 control and JAK2V617F samples; $, genes for which the differential expression was confirmed by quantitative PCR; and £, genes for which the PCR results did not confirm the array findings. Genes with no indication were not analyzed by PCR.