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Old 05-14-2019, 10:47 AM   #6
scmartin27
Quote:
Originally Posted by paulh View Post
Seems to me that the halo gene could be a modifier gene. "Individuals with a double mutant combination of modifier and target mutation have either a reduced (suppressor) or or more severe (enhancer) mutant phenotype. Many modifier genes produce a different phenotype from their target mutation, and some produce no mutant phenotype at all when the mutant allele of the target gene is not present." (From Atherley, Girton and McDonald, The Science of Genetics. Saunders College Publishing, 1999. ISBN 0-03-029232-8.) When the mutant allele of the target gene is not present, the wild type allele of the target gene is present. So analysing the inheritance relationship of the mutant modifier gene to its wild type allele requires the presence of the mutant allele of the target gene to be present.

Also, there is a difference between WC (wild caught) and wild type (WT). Wild type (AKA normal) = 1) the most common phenotype in the wild population; 2) the most common allele of a given gene in the wild population. A wild caught creature probably has a wild type phenotype/genotype and was captured in the wild. A wild type creature can be a million generations captive bred as long as it has the wild type phenotype/genotype. Wild type at the modifier gene's locus is required. Wild type at every locus is usually helpful but not required. Wild caught is not required.

A couple of more definitions:
Allele = one of two or more versions of the same gene. Alleles have the same genetic locus. Two alleles can form a gene pair. Example: In the corn snake, the motley gene, the striped gene and the corresponding normal gene are alleles. And the amelanistic gene, the ultra gene and the corresponding normal gene are alleles. However, the amelanistic gene and the motley gene are not alleles because they do not have the same locus.
Locus (plural--loci) = A particular gene's location in the genome (chromosomes/DNA in a sperm or egg). Although there are exceptions, most genes keep the same locus over the generations.

Wild type is piecemeal in nature. A given corn snake may have two amelanistic alleles at the amelanistic locus and still have two wild type alleles at the anerythristic locus and at the caramel locus and at the motley locus.

You are saying that the halo mutant allele has a locus that is independent to the amelanistic and anerythristic genetic loci, Halo phenotype occurs when a halo allele is paired with the corresponding normal allele, and green blotched is produced when the gene pair has two halo alleles. Can green blotched be identified in amelanistic corns, or does it require snow to show up? What is commonest in snow corns--non halo, or halo/green blotched? If non halo, that is the wild type allele's phenotype. Once you assign the wild type phenotype, you just need numbers and breeding results to determine whether the halo allele is dominant/codominant/recessive to the wild type allele. Matings: non halo snow with at least one halo or green blotched parent x non halo snow with at least one halo or green blotched parent, halo snow x non halo snow, halo snow x halo snow, green blotched snow x green blotched snow, green blotched snow x halo snow, green blotched snow x non halo snow. Record total number of eggs, total number raised to age where non halo, halo or green blotched can be identified, number of non halo, halo and green blotched.
I understand the genetics and the terms, thanks
I have done the majority of those breedings already (http://www.cornsnakes.com/forums/sho...d.php?t=145967) - working toward the others, of course.
As for GB being in Amels - the issue is similar to it not being visible with melanin, the red pigment "covers" it. I have seen many amels with a more orangey tone to their saddles, but I don't know if I'd say that makes them green blotched.
It already takes 6-12 months to determine if a snake is a halo/green blotched WITHOUT dealing with other pigments (red and black), so as much as I can I'm sticking with the snows / blizzards (where the yellow shows up the best & at the youngest age).