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cards-deck: default_obsidian
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#bio 

# Allele

## definition
#card/reverse 
A specific variation of a gene that produces a specific characteristic.
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## Encoding
- For each characteristic, most organisms have ==two alleles==.
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- These alleles are most often passed on encoded in chromosomes; one from mom and one from dad. 
- some organisms have just one chromosome ==(haploid)== or multiple chromosomes ==diploid, triploid, tetraploid==
- [[gametes]] only carry one allele/chromosome.
### can be dominant or recessive.
Dominant [[phenotype]] ::: at least one dominant allele. 
Recessive [[phenotype]] ::: both alleles are recessive.

#### incomplete dominance
ratio of 1:2:1, with the 2 showing a blend of the other two traits. If both are [[#^c5aafd|homozygous]].

### Alleles can be matching or not
Homozygous ::: Carries the same two alleles for a given characteristic.
Heterozygous ::: Carries one of each alleles for a given characteristic. ^c5aafd

You can tell which the parents are based off of offspring; if, for example, the offspring (3rd gen) carry the full diversity of the first generation, then the second-gen parents must necessarily be Heterozygous.