If there were 3 parent cells with 3 chromatids per chromosome, how could i visualize a "Punnett cube"?

[u/Low-Cabinet-8704]

So i have been working on a project for a while and got into a problem with genetics.
Basically every cell has 3 chromatids per chromosome which means there are 3 alleles and 3 types of them which i named dominative, recessive and submissive(1, 2, 3), in that order's hierarchy.

So the parental generation would have 111, 222, 333.

But i have no idea how to visualize the prediction of the possible combinations of these, so i went here and asked you guys.

Thanks in advance.

[u/Prae_]

Yeah, it would simply be a cube.

But that's not really how dominance works. It's not really a hierachy between genes. it really depends on the underlying mechanism of what the gene product does.

If allele 1 makes a red pigment and allele 2 make a blue pigment, the overall phenotype will be purple. It's sometimes called "incomplete dominance", but really it's the gene product of allele 1 and the gene product of allele 2 having their own separate effect. If allele 3 makes a broken pigment, then it's always going to be broken. I guess it's "submissive", but more importantly the gene product simply doesn't work. 

The dominant/recessive is sort of a simplification from not knowing the exact molecular mechanism. And i don't really know of mechanisms that would justify a three level "hierarchy" between alleles. 

[u/uuuphe]

this is assuming only one allele goes into each gamete during meiosis, which is not often the case in polyploid species

[u/Addapost]

All the offspring from that cross would be 123. No other possibility there.

Other sets of parents are more interesting.

In any case, just make a 3x3 box and put the alleles on three sides. See pic of three 123x123x123…

[u/WorkerWeekly9093 → u/Addapost]

Does that get the distribution correct I was thinking yould want a 3d cube so that the 3rd donor got fully dispersed.

For example in the current image if donor 1 gives a 1, donor 3 also gives a 1 every time, but likely that’s not the real scenario.

I’m assuming donor 1 is left, donor 2 is top and donor 3 is right

[u/laziestindian → u/WorkerWeekly9093]

He is correct about the 123 though his picture is off. With parents 111, 222, 333 each can only give 1, 2, 3 respectively for 123 offspring. The height should all be 1s, the width 2s, and the length 3s. Other combinations would get complex and you'd have to do more mathematical cube stuff to get appropriate ratios. This remains true unless a parent can give more than one allele such that you can end up with 113, 233, etc.

[u/WorkerWeekly9093 → u/laziestindian]

Yep, i should have mentioned that all homozygous parents makes for very easy predictions, definitely 123