Posted by:
RandyRemington
at Wed Aug 2 07:31:52 2006 [ Email Message ] [ Show All Posts by RandyRemington ]
Alleles are DIFFERENT versions of the same gene. So the theory that mojave and lesser are alleles isn't the same as saying the are the exact same mutation, just in the same place.
I haven't seen a ton of results from breeding the cross line leucistics to normals but so far the ones I've seen where consistent with the allele theory, no normals and no leucsitics, only the two grandparent types about 50/50.
It's possible that something similar might be happening with hypomelanistic and axanthic complicating the production of true ghost. If the original double hets are normal looking then axanthic and hypomelanistic probably aren't alleles but the might be mutations of genes that just happen to be close together on the same chromosome. There may be more known individual mutations than chromosomes now and if so it's inevitable that as we try to make combos we will eventually find mutations linked by being on the same chromosome.
When a double het parent is picking which genes to pass on to it's offspring it tends to make a copy of one of its pairs of each chromosome. If hypomelanistic and axanthic are on the same chromosome then the double het has one of each version but tends to pass on a copy of only one or the other. The only way it could pass on a version of that common chromosome with both mutations would be if there where an odd number of crossovers between the two mutant genes while making the copy to pass on from the two originals. Depending on how frequent crossovers are and how close together the two mutant genes are it might take a while breeding double hets to make that first copy of the common chromosome with both mutations.
Now I don't know if double hets for true ghosts have really been breed long enough to make a true ghost all that conspicuous by it's absence and linkage being at all particularly likely for that pair but we are likely to eventually see it somewhere.
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Alleles and Linkage - RandyRemington, Wed Aug 2 07:31:52 2006