Heterozygous

You have two copies of each of your 23 chromosomes, one inherited from each parent. The terms homozygous and heterozygous describe whether your DNA sequence is identical or different between these two chromosomes at a specific position. If you are heterozygous at a specific position, this means that your two chromosomes are different. For example, say that a specific variant in the genome can have two different base pairs, either an “A” or a “G”. A person who is heterozygous would have a “A” base pair on one chromosome and a “G” base pair on the other chromosome. A person who is heterozygous at a specific genetic location is called a heterozygote.

Homozygous

You have two copies of each of your 23 chromosomes, one inherited from each parent. The terms homozygous and heterozygous describe whether your DNA sequence is identical or different between these two chromosomes at a specific position. If you are homozygous at a specific position, this means that your two chromosomes are identical. For example, say that a specific variant in the genome can have two different base pairs, either an “A” or a “G”. A person who is homozygous would have an “A” base pair on one chromosome and an “A” base pair on the other chromosome. They could also have a “G” base pair on both chromosomes. A person who is homozygous at a specific genetic location is called a homozygote.

Compound Heterozygous

You have two copies of each of your 23 chromosomes, one inherited from each parent. The term heterozygous describes DNA that is different between these two chromosomes at a specific position. If you are compound heterozygous, this means that you are heterozygous for two different variants within a specific gene. A person who is compound heterozygous is called a compound heterozygote.