An organism or individual that carries two different versions (alleles) of a particular gene, one inherited from each parent.
From Greek 'hetero-' (different) and 'zygote' (yoke/joined pair); term dating to early Mendelian genetics for organisms with mixed genetic inheritance.
If you're a heterozygote for eye color, you might have one gene for brown eyes and one for blue—and which one shows depends on which is dominant, making you a living example of genetic lottery.
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