To HHmoore: Yes that is one of the types of IMG's we have seen. We see many babies that we think have the trait, then end up doing that instead of the bleach and black. These that slowly grey in the scales in my experience have never gotten really dark.
To the boidsmith:
Ontogenic means age onset-this trait takes at least 16-18 months and 500-600 grams before it starts to show in all of the examples we have now.
Why do some turn a little dirty like what hhmoore has pics of, or why do some turn 95% black, why do some bleach first, and some just do a slow burn. The reason for these are unknown. But it is 100% genetic, but it not currently produced with calculatable inheritance. Bill Albright was the first other person I ran into that had held onto anything for 2 gens after the initial discovery. When we chatted with each other we both discovered that our animals went throught the same steps at the same time. This cannot simply be coincidental.
I know of over 100 of these animals, in almost a dozen peoples collections I have seen them in normals brought in from Noah's farm, Patrice's farm, in cbb normals, the spider that was just shown, a couple of pastels, and a yellowbelly. I know of someone holding back about 75 babies from img X img, and img x normal from 06 hatch. A few have changed, and several look like they might. We are still collecting data and it is screwy.
I believe that this will be somewhere along the lines of granite, where some lines prove, other lines don't, and to be safe the propective buyer is going to have to buy a small adult that has bleached, or is toasting up.
Conditional alleles explain why some lines would prove and some wouldn't. They function in many ways but a super simplified example is here:
A conditional allele is an allele that codes for a certian protien/process/mechanism. Beside it sits another set of dna that codes for something else that may or not be a related mechanism. When they are passed from the parent to the offspring together everything works right, but if the chromosome happens to split the dna chain between them, they loose thier funtion.
Or, you could have a situation where a set of dna that covers a certain genotype that leads to a visable phenotype is 750 base pairs long in its chain. DNA splits and gets one copy form mom and one copy from dad to make a single whole offspring. Say it splits this particular dna chain in half but moms side isn;t exactly alike it may or may not change the function of that dna chain. Many times a point mutation (one single base pair mutation) leads to nothing. However if you change a bunch of the base pairs it can alter how that mechansim/protien that was given rise to by that dna chain is produced/ or funtions. It may totally wipe it out.
Actual bench top lab work will need to be done to figure this out, but cost, lack of interest from the science field, and the fact that I would need to put down a bunch of animals/eggs to get samples throughout life limit how much will acutally be done.
Gotta run for now, but let me know if you have any quesitons