Such studies show that chromosomal alterations can be found in cis of existing mutations (i.e., overlapping the mutated locus), thereby contributing to an increase in mutant allele dosage, e.g., 9pCNLOH and JAK2 in myeloproliferative neoplasms (MPN) or bi-allelic inactivation of tumor suppressors, e.g., TP53 and 17pLOH32. The gene discussed is JAK2; the disease is myeloproliferative disorder.