Question about GFP

[Jenste]

GFP is still a bit over my head as far as genetics...

If you mate a GFP with a nonGFP, what would you get? Would the GFP be lost or would it be 50/50?

Use these scenarios as an example
1) a non GFP Golden Albino male to a GFP Albino Female
2) a GFP male Wildtype to a non GFP female Wildtype?

What would offspring possibly look like?

 

[ZombieAxolotl]

1) Albino with a 50% chance of GFP offspring
2) Wildtype with a 50% chance of GFP offspring

Now not knowing the genetics, and if those parents carry for anything you could end up with more color types.

To put it simply... GFP is not "dominant"... but it's dominant LOL.
So if you breed a GFP to a non-GFP, in a perfect world 50% of your offspring will express GFP.

In this 2" clutch I have now, it's a non-GFP melanoid x GFP wildtype. I did the breeding to determine what the male carried for.
The clutch was as follows.

Lucy- 19
Lucy GFP- 24
Melanoid- 16
Melanoid GFP- 12
Wildtype- 33
Wildtype GFP- 44
Total:
GFP- 80
Non-GFP-68

Which is more then the 50% expected obviously.. sometimes you can get as few as 30% it really just depends. There is also some thought into a GFP that carries 2 GFP genes will produce larger number of GFP offspring.

Hope that helps.

 

[jinian]

GFP exactly fits the definition of dominant: with one copy of it, you see GFP. (It's possible for some lines to be only semi-dominant, where animals with two copies are brighter, but normally you can't tell by looking.) Thanks for the numbers, Katie; they look exactly like what I'd expect from relatively small numbers of animals approximating a 50/50 ratio, which as you know means your guy is het for GFP.

So in the original question, if the GFP parent in each cross is homozygous for GFP, all the offspring should have GFP. If they're heterozygous, half and half.

It's possible that this could be a lot more complicated, but I think there's probably just the one GFP locus in the hobby trade so I'll leave it at that unless people are raring to hear more about transgenics.

 

[Jenste]

Thank you guys! I was just curious. I don't have a GFP axie but I was curious as to what types of offspring could result if I ever did get one.

Does it matter if the male or female is the GFP?

 

[michael]

I think gfp is a little more complicated than that. Some gfp express the gene stronger than others. You can usually tell by looking at the adult. My experience suggest gfp to gfp results in nearly all gfp. Non gfp to gfp is a mix. It is something more than recessive but not completely dominant. What does that mean?

 

[jinian]

Jenste: As far as I know GFP in axolotls is not sex-linked. It would be annoying to work with, so the scientists wouldn't breed any that came up that way. So no, male or female shouldn't make a difference.

Michael: Yes, it can get more complicated in practice. Based on what you describe, there are two reasonable scenarios.

1. Multiple insertion loci of GFP in the axolotl genome. We obviously have stable transformants (since they can have GFP offspring), so that means the GFP gene is integrated into their DNA somewhere. If there were one place it was inserted, GFP would act like any ordinary gene controlling a single trait, and we'd see the perfect Mendelian segregation I was assuming in my previous response. However, if there are two different places in the genome that GFP is present, you could get something resembling a dihybrid cross. (Dihybrid cross - Wikipedia, the free encyclopedia -- the green square in the figure would be the only axolotl without GFP.) And there might be even more than two. In my experiments I make multiple lines of any transgenic, so different GFP loci almost certainly exist, and I have no idea how or how many times GFP axolotls have reached hobbyists.

2. GFP sometimes gets silenced. I see this in my transgenics all too often. Even though the gene is inserted stably in the genome, sometimes the cells can "catch on" that there's something that doesn't belong there. We don't know exactly how it works in every organism, but you can see where it would be really useful for resisting viral infection: if a virus comes in and starts making a ton of copies of itself, the organism whose cells can respond by shutting down production of that virus will be a lot healthier than one that doesn't "notice". So you'd stop getting a protein made from the silenced gene, and you wouldn't see GFP any more. Usually the silencing is heritable, so the offspring would carry GFP but also carry the cellular "memo" not to make any.

Without doing crosses specifically to evaluate these hypotheses, it's hard to tell what's going on for sure, and there could easily be elements of both.