# Recessive yellow-how does it work?



## moustress (Sep 25, 2009)

What is the order of precedence in the expression of recessive yellow? Does it only show when the A locus is homozygous for the recessive a? Is it subordinate to any other dominant genes?


----------



## Lizzle (Apr 7, 2010)

I got this information from this site: http://www.hiiret.fi/eng/breeding/genetics/a-locus.html (Love this site!)

Here is the order of precedence according to the above site (1 being the most dominant):
1. Ay - Lethal dominant yellow
2. Avy & Ahvy - Viable yellow & hypervariable yellow
3. Aw - White-bellied Agouti
4. A - Agouti or Wild type
5. at - Black and Tan
6. am - mottled agouti
7. a - Non-agouti
8. ae - Extreme non-agouti

I've never heard of 'recessive' yellow before, though. Do you have a picture example, maybe?
I get the impression that you're saying that 'recessive yellow' is not on the A locus? Hmm, I want to find out more about this too, if that is the case.


----------



## jessilynn (Jul 9, 2010)

Recessive Yelow (RY) Is the most common yellow in the US.


----------



## Lizzle (Apr 7, 2010)

I am rather baffled now. :lol: I have hypervariable yellow in my lines, but recessive yellow? Don't think so. What locus, if not the A locus, is this gene located on?


----------



## HemlockStud (Apr 26, 2009)

lizashley said:


> I am rather baffled now. :lol: I have hypervariable yellow in my lines, but recessive yellow? Don't think so. What locus, if not the A locus, is this gene located on?


The recessive yellow gene is located on the E locus.


----------



## neurozool (May 22, 2010)

Viable yellow (Avy) Second on that list is 'recessive yellow'. It is called viable as it is not lethal like Ay is.  Hope that helps!

This link helps explain why the term 'viable' is used: http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=iga&part=A630#A640


----------



## SarahY (Nov 6, 2008)

On 'A' and 'a' recessive yellow (e/e) works much the same as dominant yellow, turning the mouse into a red regardless of whether it's agouti or black based. Chocolate and blue have no real effect on recessive yellow, it covers both of these up, and pink eye dilute turns the red into a fawn with pink eyes.

I don't know how it'd work with anything other than 'A' and 'a' though, sorry!

Sarah xxx


----------



## WillowDragon (Jan 7, 2009)

Blue can (I have been told, and seen pics) make recessive red paler though. I don't know why! hehe

I believe (though i may be wrong) that recessive red, is the same as the red (chestnut) gene in horses... when in hetrozygous form it is totally covered by any other gene present on the Loci... but when homozygous, it is completely dominant.

W xx


----------



## SarahY (Nov 6, 2008)

Blue dilutes dominant yellow to a buff colour, but has no effect on recessive yellow.


> when in hetrozygous form it is totally covered by any other gene present on the Loci... but when homozygous, it is completely dominant.


That sounds right - which would mean that it would cover up all of the 'a' locus varieties, even tan.

Sarah xxx


----------



## neurozool (May 22, 2010)

Well, in the US at least, when we use the term recessive yellow, it is referring to Avy. It is called recessive here as it is recessive to Ay. I believe the full genotype is Avy/(anything other then Ay) e/e.

It might be different in the UK as recessive yellow is near impossible to find. Liz and moustress live in the US though, so the answer to that question would be that recessive yellow is dominate to all other colors but lethal yellow (which is very rare here) and is also called viable yellow.


----------



## SarahY (Nov 6, 2008)

I have never heard of Avy being called recessive yellow, in the US or anywhere else. I've always seen it referred to as viable yellow or (American) brindle. Avy/* is a brindle mouse, Avy/* e/e is a brindle with yellow stripes so it looks like a solid yellow, and A/* or a/* e/e is a solid yellow mouse.

Recessive yellow (e/e) is so called because its truly recessive, unlike viable yellow which is dominant to everything except dominant (lethal) yellow. A mouse that is a/a E/e is a black carrying recessive yellow, an a/a e/e is a recessive yellow. Viable yellow is not recessive because it can't be carried.

Regardless of that, recessive yellow isn't a standardised name (and could be as vague as sepia, which seems to mean all kinds of c-locus browns) so really I suppose we need to know which type of yellow moustress is referring too :lol: :lol:

Sarah xxx


----------



## Lizzle (Apr 7, 2010)

Oh! Now it makes much more sense to me. I was under the impression that there was some special 'recessive yellow' that I was totally unaware of. :lol: Yes, Avy is recessive to only Ay (lethal) on the A locus.

Forgive this silly question.. but what does the E locus control? I've honestly never read about it, I don't believe.


----------



## SarahY (Nov 6, 2008)

'e/e' just changes the colour to yellow, like 'd/d' makes a black mouse blue and 'b/b' makes a black mouse chocolate. Only difference is, e/e overides agouti as well - A/* e/e and a/a e/e look the same.

Sarah xxx


----------



## moustress (Sep 25, 2009)

Thanks; that confirms what I thought. Just wanted confirmation as there is a real lack of info out there about recessive yellow.


----------



## windyhill (Jan 19, 2010)

Ive been working on recessive yellows for awhile, but I hate how their is a lack of info about them.


----------



## moustress (Sep 25, 2009)

Well, I think we just took care of that didn't we!


----------



## WNTMousery (Jun 2, 2010)

neurozool, in the US Recessive Yellow is NOT Avy. Avy is American brindle. Recessive Yellow is a totally separate gene located on a different locus.

Recessive yellow is indeed affected by blue. Many US fanciers call Blue-based RY "hidden treasure" but I call it "ugly." Before I even knew about exhibition breeding, I had this "hidden treasure" pop up in a pet typed litter I bred. I've seen it first-hand and I know I have pictures but not sure where they are at the moment.



SarahY said:


> A/* e/e and a/a e/e look the same.
> 
> Sarah xxx


This is not true. Just like with Dominant Yellow, black will "muddy" the color on a Recessive Yellow. The rich, desirable color of Recessive Yellow is best displayed when paired on a Cinnamon background, just the same as Dominant Yellow.


----------



## neurozool (May 22, 2010)

LOL- my mistake! I just figured out what I was thinking about! My first mouse was a undermarked brindle (Avy) to the point where she looks just like a recessive yellow.  I am sooooo sorry! Thank you WNT- I was VERY turned around...very very very!


----------



## SarahY (Nov 6, 2008)

> Recessive yellow is indeed affected by blue.


You're right - I was having a blonde moment :lol: It's _Leaden_ blue that doesn't really affect yellow pigment.



> This is not true. Just like with Dominant Yellow, black will "muddy" the color on a Recessive Yellow. The rich, desirable color of Recessive Yellow is best displayed when paired on a Cinnamon background, just the same as Dominant Yellow.


I wasn't talking about the best way to get a bright yellow. I was saying that yellow won't display ticking so an agouti based yellow would still look yellow, not 'yellow agouti'.

Sarah xxx


----------



## Lizzle (Apr 7, 2010)

Let's say you have Avy x what you believe to be a chinchillated agouti carrying c (the latter's parents being a PEW and a blue cch with white patches.

The babies you get turn out mostly 'yellow' - some a very muddied yellow, one definitely brindled, and the rest appear to be just yellow with white tummies.

Could this be an example of the recessive yellow coming through via breeding? If so, I'm pretty sure that sounds like what I have in one of my current litters. If not, I'm completely confused again. :lol: Does anyone have a link to further info?


----------



## WNTMousery (Jun 2, 2010)

lizashley said:


> Let's say you have Avy x what you believe to be a chinchillated agouti carrying c (the latter's parents being a PEW and a blue cch with white patches.
> 
> The babies you get turn out mostly 'yellow' - some a very muddied yellow, one definitely brindled, and the rest appear to be just yellow with white tummies.
> 
> Could this be an example of the recessive yellow coming through via breeding? If so, I'm pretty sure that sounds like what I have in one of my current litters. If not, I'm completely confused again. :lol: Does anyone have a link to further info?


You likely just have un-marked brindle that appear yellow.


----------

