Biology / Unit 5 Bio 1029 short lesson, about 20 seconds
Homozygous and Heterozygous
Captions available
The idea
A homozygous genotype carries two identical alleles at a locus; a heterozygous genotype carries two different alleles at that same locus.
In practice
A dog with genotype BB or bb for coat color is homozygous; one with genotype Bb is heterozygous.
Where people slip
Homozygous and heterozygous describe one locus at a time — an organism can be homozygous at one gene and heterozygous at another.
Your place on the trail
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