So true, Candy.
Yeah, it would have been fun to get to the bottom of this. We can make educated guesses if lots of people contribute their experiences with gliders from this lineage; but as far as I know, even with their accounts there will be no way to know with certainty if it is x-linked partially, completely, or not at all.
IF we knew for certain that it bred out completely every time after one producing male and his son, then we could conclude it was x-linked. If any infertility lingers at all after a producing male and his son, then it is either partially x-linked or not x-linked at all.
The most important question is: is there any non x-linked portion of it that is dominant? If it lingers after a producing father and his son, and especially if it tends to run in families despite being very bred out (low coi and breeding to lines without sterile mosaics in it), then it most likely is dominant.
If it was dominant about half of the joeys would have the lessened fertility and pass it on. You would be able to see it, but not without breeding the animal, and even then it may not be obvious, especially in females. By the time you figure it out they may already have grandchildren about half to a quarter of which would also have the defect and you would not know which ones until you bred them (and some may slip through the cracks even then).
It would theoretically eventually become less and less % of the population every generation but would never completely breed out of the population like a recessive gene unless we started selecting it out like nature does (by not breeding effected individuals or their offspring). It would be VERY difficult to breed out of a recessive color population, if it somehow got in. I'm not pretending to know if this is happening. I have no idea. I hope not. And this is not a special scenario for this gene, this would be the case for any dominant gene that remains hidden until after the animal has had offspring. Again, I'm NOT saying this is happening, I mentioned the signs above that would suggest it is happening, I'm just explaining what would be the prognosis if we did find out this includes a dominant gene.
And Nancy, with your mosaic family, yes, this COULD be because your animals are from sterile lines and it has not been completely bred out; it would be the most likely scenario; especially since this male is first generation from sterility (it would be interesting to know how his sons would produce) But with a sample size of 2, the standard deviation will be very close to 2. Simply meaning that we cannot draw conclusions for the whole population based on 2 animals. Like I said, if we were seeing trends like this, it would become very suspicious. But with just 2 animals, although it is likely, it COULD also be anything: maybe they have another mutation and are pulling joeys because of it, maybe they aren't eating all their food and their nutritional balance is not ideal for breeding, maybe they have a completely different mutation for fertility issues ... The list is endless.
Thank you for being willing to say so and help with the greater good of the gliders in this line! And I want to make sure I say that I am in no way implying that your animals have bad genetics or are not healthy, I'm just saying there are endless reasons this could be happening to anyone's animals; the sterility in the line makes it suspicious, but that is all, no conclusions can be drawn.
And I want to make sure not to be confusing, I am NOT saying your animals are showing evidence of the dominant gene I spoke of above. You would have to breed a son of your male to contribute to any evidence for or against that.
If the community wanted to get an educated guess about what is going on, they would need lots of breeding accounts from this line; both the females and producing males; whether mosaic or not; but with sterile line mosaics in their ancestry. How far are they from the sterility and how do they produce (some of the females may still be producing sterile; do they show any other symptoms?)? and if you got really ambitious, even map out which family lines seem to have this lingering problem (if there is any lingering problem). This is up to people who know mosaics and have a vested interest in their line; if they decide it is important to them to know. I do not know mosaics; but think they are beautiful animals and wish them and their pet people long, healthy, fruitful lives