What's the difference between these two conditions? I know what a het is but i have no idea what a homozygonous is.
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Heterozygonous and Homozygonous
tyler1055
Apr 05, 2005 12:08 AM
Replies (2)
Sonya
Apr 05, 2005 12:24 AM
>>What's the difference between these two conditions? I know what a het is but i have no idea what a homozygonous is.
homozygotes have identical genes for a trait. Heterozygotes have a dominant and recessive gene for the trait. The dominant gene trait shows in the makeup of the animal and the recessive gene doesn't until it is matched with another recessive gene. So, if you have two animals that are 'Het' for the same trait and you breed them you have a chance of getting that trait come out homozygous.
Okay, not sure how clear that is....it is late....er early, here.
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Sonya
Haven't we warned you about tampering with the structure of a chaotic system?
Mrs. Neutron
chrish
Apr 05, 2005 06:59 AM
Most reptiles (and other animals that you would normally think of) are diploid. This means they have two copies of each chromosome (strand of DNA). Because they have two copies of each chromosome and the genes are on the chromosomes, they must have two copies of each gene. One copy comes from each parent. These two copies are called alleles.
Therefore, because you have two copies of each gene (two alleles) you can either have two copies of the same version of the gene or your two copies can be different. If your two copies match, you are homozygous. If your two copies don't, you are a heterozygous.
So for example, 4 o'clock flowers have a gene that affects flower color. They either have a red version or a white version of the gene. Each plant has two copies, therefore the plant can have
- two red copies (homozygous red - produces red flowers)
- two white copies (homozygous white - produces white flowers)
- one red and one white (heterozygous - produces pink flowers)
What the heterozygote looks like depends on the nature of the two alleles. Some alleles are both expressed (like the flowers) while others produce nothing and are therefore hidden by the alternate (dominant) allele. So a cornsnake that is heterozygous for albinism has a copy of the albino allele, but it is hidden by the other normal allele.
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Chris Harrison
