Heterozygous describes a pair of genes for a trait where the two versions (alleles) are different, such as one dominant and one recessive allele. An organism that is heterozygous may show the dominant trait but still carry the recessive one.
From Greek “hetero-” meaning “different,” and “zygous” from “zygon,” meaning “yoke” or “pair,” related to “zygote.” It literally means “having different pairs” of genes.
If your genes are like paired cards, being heterozygous means you’re holding two different cards for the same trait. You might look like one card on the outside (the dominant one) while secretly carrying the other. That hidden card can suddenly reappear in your children or grandchildren, which is why family traits sometimes skip generations.
Complete word intelligence in one call. Free tier — 50 lookups/day.