| hemizygous | <genetics> A situation within a cell where only one copy of a gene or group of genes is present instead of the usual two copies per gene in a diploid genome. The word is used as in the following example: the cell is hemizygous for gene X. (09 Oct 1997) |
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| hemizygous gene | <genetics> Any gene which is present as only one copy in a diploid genome, when most other genes in the genome are present as two copies. The genes on the sex chromosomes of members of the heterogametic sex of a species are all hemizygous genes (for example: in humans, males have hemizygous genes on their X and Y chromosomes because they do not have two copies of either of those chromosomes). (13 Nov 1997) |