Thoughts on cinnamon and enchi being allelic?

[paulh]

This discussion does not seem to adress the question of whether enchi and cinnamon might be linked. Two genes are linked if the two loci are close together in the same chromosome. With over 200 mutants known but only 18 pairs of chromosomes, it seems likely that there ought to be some linkages. Ball pythons have a relatively small number of eggs, and there would have to be controls for parthenogenesis and retained sperm, so results from a few clutches may not be enough to prove anything.

As far as I know, pastel and spider mutant genes are not linked. When a pastel spider ball python is bred to a normal, 25% of the babies are expected to be normal. And 25% of the babies are expected to be both pastel and spider. If two mutant genes are closely linked, possibly as few as 1% of the babies would be normal, and 1% would be crossovers. And if we control for parthenogenesis and the normal parent is female, we'd have to delete the normal babies from consideration.

[nikkubus]

This discussion does not seem to adress the question of whether enchi and cinnamon might be linked. Two genes are linked if the two loci are close together in the same chromosome. With over 200 mutants known but only 18 pairs of chromosomes, it seems likely that there ought to be some linkages. Ball pythons have a relatively small number of eggs, and there would have to be controls for parthenogenesis and retained sperm, so results from a few clutches may not be enough to prove anything.

As far as I know, pastel and spider mutant genes are not linked. When a pastel spider ball python is bred to a normal, 25% of the babies are expected to be normal. And 25% of the babies are expected to be both pastel and spider. If two mutant genes are closely linked, possibly as few as 1% of the babies would be normal, and 1% would be crossovers. And if we control for parthenogenesis and the normal parent is female, we'd have to delete the normal babies from consideration.

Linkage wouldn't make sense for the results people get. If linked, a Cinnamon Enchi would produce a bunch of normals and Cinnamon Enchi's and rarely any with one or the other. because they would be passing down together from the same parent. Not to mention producing a Cinnamon Enchi in the first place would be more difficult than average odds.

It's been way more than a few clutches at this point to test the theory.

[paulh]

Linkage wouldn't make sense for the results people get. If linked, a Cinnamon Enchi would produce a bunch of normals and Cinnamon Enchi's and rarely any with one or the other. because they would be passing down together from the same parent. Not to mention producing a Cinnamon Enchi in the first place would be more difficult than average odds.

It's been way more than a few clutches at this point to test the theory.

Gene symbols:
E = enchi mutant gene
e = normal gene
C = cinnamon mutant gene
c = normal gene

Chromosome pair of a cinnamon enchi from a cinnamon x enchi mating:
---------e------C---------
---------E------c---------
This is a trans linkage, because the two mutants are on different members of the chromosome pair. Almost all of this snake's babies (if mated to a normal ball python) would be either enchi or cinnamon.

A cis linkage would put the two mutants on one chromosome and the two normal genes on the other chromosome.
---------E------C---------
---------e------c---------

You are writing about a cis linkage, and what you wrote is true.
I was writing about a trans linkage, which gives totally different results.

I have not seen the results of any cinnamon enchi x normal matings. By all means beat me into submission with numbers. But to be convincing, the data must include genotype of male, genotype of female, is female virgin, total number of babies, number of cinnamon enchi babies, number of cinnamon babies, number of enchi babies, number of normal (neither cinnamon nor enchi) babies. The number of clutches means nothing. If possible, get at least 100 babies in the data.

[nikkubus]

Gene symbols:
E = enchi mutant gene
e = normal gene
C = cinnamon mutant gene
c = normal gene

Chromosome pair of a cinnamon enchi from a cinnamon x enchi mating:
---------e------C---------
---------E------c---------
This is a trans linkage, because the two mutants are on different members of the chromosome pair. Almost all of this snake's babies (if mated to a normal ball python) would be either enchi or cinnamon.

A cis linkage would put the two mutants on one chromosome and the two normal genes on the other chromosome.
---------E------C---------
---------e------c---------

You are writing about a cis linkage, and what you wrote is true.
I was writing about a trans linkage, which gives totally different results.

I have not seen the results of any cinnamon enchi x normal matings. By all means beat me into submission with numbers. But to be convincing, the data must include genotype of male, genotype of female, is female virgin, total number of babies, number of cinnamon enchi babies, number of cinnamon babies, number of enchi babies, number of normal (neither cinnamon nor enchi) babies. The number of clutches means nothing. If possible, get at least 100 babies in the data.

You are correct about trans linkage, I made a logic error when I wrote my last post.

There is data like what you describe but usually not in a nice neat presentation, it takes listening to people drone on in videos with the exception of viewing JKR/Kinova clutch records.

Another thing I might mention is that many other combinations besides Cinammon Enchi have being tried, and while it's still not 100%, it does point towards allelic when other morphs considered allelic with Cinnamon behave the exact same way with Enchi. Of course if they are all linked, they would until you saw crossover. I guess it's always possible they are closely linked and we just haven't seen crossover, but for me personally, there is enough data for me to consider them allelic until proven otherwise given they are going to behave exactly as if they were in odds until that happens, and then whatever line does crossover, they will start behaving as if they are a single morph, difficult to pull apart.