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Pertaining to a gene of which only one copy is present in an organism having diploid cells. In human beings, refers to genes on the X chromosome in males, which are expressed whether dominant or recessive.
Farlex Partner Medical Dictionary © Farlex 2012
Having unpaired genes in an otherwise diploid cell; males are normally hemizygous for genes on both sex chromosomes.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
hemizygous(of a DIPLOID (2) organism) possessing only one allele of a gene, rather than the normal two. For example, male mammals have only one copy of each gene on the single X-chromosome. see SEX LINKAGE.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005