JAK2 and myeloproliferative neoplasm: Mutability landscape of JAK2-negative myeloproliferative neoplasm. For two most likely recurrent trees TFRG and TASNS identified above, more detailed analysis of their mutability landscapes using the general MULAN model demonstrated that in both cases the increase in the inferred mutation rates is likely associated with the emergence of mutation in the gene SESN2 (Fig 6).