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Cornsnake Morph Guide ®

Advanced Genetics

Charles Pritzel

Heterozygous (BW) specimens could have any number of different "third phenotypes." The phenotypes on the right could be described as "codominant" since both the black and white genes are fully expressed in their own areas.

Here are some "shades of gray" examples that would fit the "incomplete dominant" subgrouping.

But this can become an oversimplification. Not all examples fit perfectly into a clear subgroup:

Are the alleles "incomplete dominant" because the phenotype is gray, or codominant because it is made of individual black and white areas? This example could fit both descriptions. Click the picture to zoom in and out.

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Other topics that may someday apply to cornsnake genetics are trait linkage and sex-linked traits. So far, neither of these have been positively identified in cornsnakes. At some point in the future they will, and a discussion of these concepts may prove useful in an effort to identify such traits by their "odd" behavior.

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Chromosomes and linkage

Chromosomes are large groups of genes that are physically connected to each other. Because of this, genes that are on the same chromosome will often stay together. This is called linkage. The consequence of this is that linked traits will not "sort independently."

Independent sorting is like flipping two coins: the way one coin lands has no effect on what the other coin does. They are independent of each other. A very strong linkage is similar to taping two coins to each other. Now when you flip the two coins, the two results will show a relationship to each other, either always the same or always the opposite.

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