Clonality Studies: Clonality is based on the principal of X-chromosome inactivation and thus, for clonality studies only females can be used as subjects. It is based on the principal that while female cells have two X-chromosomes, one is randomly inactivated during early embryonic development and thus female tissue is a mixture of cells expressing either paternal or maternal inherited x-chromosome genes. In the first step, DNA analysis will study 5 exonic polymorphisms for the X-chromosome genes which have previously been shown to be useful for these purposes. If any of the five loci is heterozygous then the subject is said to be informative for clonality. Studies which will proceed as follows: The fresh blood platelets and granulocytes will be isolated and the RNA isolated and used later for reverse transcription to cDNA which will then be analyzed for X-chromosome allelic usage ratio by single-stranded conformational polymorphisms (SSCP). If only one allele is expressed in platelets or granulocytes the patient is said to be clonal and favors a diagnosis of myeloproliferative disorder (such as AMM), while polyclonal blood (both X-chromosome alleles expressed in platelets and granulocytes) is compatible with secondary myelofibrosis.