Genotype of light steel?

[user 8990]

Hello everyone! I’m new to steel genetics and have some questions about it.

Is the kit in the foreground light steel? What is the genotype for this color?

 

[user 8990]

Pretty sure that the kit on the left is a gold tipped steel.

 

[Alaska Satin]

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Pretty sure that the kit on the left is a gold tipped steel.

Yes, I'd agree that is a steel, which looks a lot like an agouti without the "trim" (because that's what it is). A steel, aka gold-tipped steel, has at least one copy of the agouti gene and one copy of the steel gene): A_B_C_D_Es_

The broken kit is hard to say from these pictures; it could be either steel or chestnut, as they look a lot alike at this age except the trim, which a broken mostly doesn't have since it's white in those areas.

I'm not sure what you mean by "light steel." There is gold-tipped steel and silver-tipped steel, the latter of which has the yellow pigment removed by the chinchilla gene (i.e. A_B_cchd_D_Es_). The kit in the foreground has yellows in its fur so it's either agouti (aka chestnut) or steel (gold-tipped). If you meant "light gray" as in Flemish Giants, that is actually another name for chinchilla, not steel. Chinchilla is A_B_cchd_D_E_.

Incidentally, the colors of both brokens look suspiciously brindled. Is there harlequin in the background?

 

[user 8990]

Yes, I'd agree that is a steel, which looks a lot like an agouti without the "trim" (because that's what it is). A steel, aka gold-tipped steel, has at least one copy of the agouti gene and one copy of the steel gene): A_B_C_D_Es_

The broken kit is hard to say from these pictures; it could be either steel or chestnut, as they look a lot alike at this age except the trim, which a broken mostly doesn't have since it's white in those areas.

I'm not sure what you mean by "light steel." There is gold-tipped steel and silver-tipped steel, the latter of which has the yellow pigment removed by the chinchilla gene (i.e. A_B_cchd_D_Es_). The kit in the foreground has yellows in its fur so it's either agouti (aka chestnut) or steel (gold-tipped). If you meant "light gray" as in Flemish Giants, that is actually another name for chinchilla, not steel. Chinchilla is A_B_cchd_D_E_.

Incidentally, the colors of both brokens look suspiciously brindled. Is there harlequin in the background?

Oh I definitely have to find the time to research this more thoroughly! Thank you for your assistance!

I was confused by the internet again. Light steel is the color that people have called this on websites. They are continental Giants.

Okay, so I am not seeing any ej in the pedigree. However they were line bred to a BEW import and the pedigree ends there. So while it’s not visible, harlequin is entirely possible.

The sire definitely carries chin. So this is potentially harlequinized chin? If so, what color chinchilla? I’ll get better photos of the four kits that color.

 

[user 8990]

Correction. Harlequinized silver tipped steel??

 

[user 8990]

 

[Alaska Satin]

I was confused by the internet again. Light steel is the color that people have called this on websites. They are continental Giants.

Yes, the different common names for colors can vary widely among different breeds and especially among different countries. Some have argued they should be standardized, but I prefer the localized names and the history they bear. And it also ensures a permanent place for genetics nomenclature!

Looking at the Continental Giants in USA Group's page Conti Standards – Continental Giant Rabbit it appears that the BRC recognizes Black, Dark Steel Grey, Light Steel Grey, Opal, Yellow, Chinchilla, 2 varieties of Agouti (Chestnut & Red), & 2 varieties of White (REW & BEW).
From the description on their color page Conti Colors – Continental Giant Rabbit I'm guessing that dark steel is STS and light steel is GTS, given that the light steel description includes mention of a sandy/brown band and gold/brown tips on the hairs. Also, the photos here Continental Giant Rabbit: Facts, Temperament, Care, with Pictures show what look like a GTS and STS under the headings "Light Steel" and "Dark Steel."

If so, the Light Steel genotype would be GTS <A_B_C_D_Es_> and Dark Steel would be STS <A_B_cchd_D_Es>.

Okay, so I am not seeing any ej in the pedigree. However they were line bred to a BEW import and the pedigree ends there. So while it’s not visible, harlequin is entirely possible.

Yes, that BEW can certainly hide the <ej> and looking at those new photos, I'd say it did!

The sire definitely carries chin. So this is potentially harlequinized chin? If so, what color chinchilla? I’ll get better photos of the four kits that color.

Correction. Harlequinized silver tipped steel??

Because it has no discernible reddish tones, I'd call the first kit magpie, which is the name for a harlequinized chin or a chinchilla harlequin <A_B_cchd_D_ej_>, in fact it's probably a VM magpie <A_B_cchd_D_ej_Vv>. The chinchilla allele <cchd> removes most yellow pigments, leaving pearl bands where the rufus would normally be; the ej allele causes those black and pearl colors to appear on separate hairs rather than in bands on the same hair. The Vienna gene, as you know, causes white spots, which are sometimes harder to pick up in magpies since they have white areas as well. However the Vienna gene you're dealing with seems to cause very extensive white areas, more extensive than you'd normally expect on a magpie (though that can vary dramatically too).

I'm not sure about it being VM harlequinized silver-tipped steel (STS) <A_B_cchd_D_Esej>. I have never had direct experience with combining Es and ej and don't really know how those would interact. The Es allele basically squishes all the agouti banding up to the top of the hairshaft, while the ej allele removes the black and silver bands and distributes those pigments onto different hairs; not sure how that would play out when you put them both on the same rabbit. @judymac may have some insight regarding that.

I'd probably call the second kit VM harlequin <A_B_C_D_ej_Vv> given the reddish tones in its fur. However, to make things even more complicated, chinchillas frequently have rustiness across their backs as kits, which molts out eventually; so that could go either way. In my chins the rustiness molts out somewhere around 3 months or more.

Those are pretty cool looking rabbits, by the way. I love the combination of Dutch-looking VM with the magpie/harlequin. A friend just had a harlequin Dutch appear in one of her litters - she calls it her bumblebee bunny. It's so dramatic, we're wondering why it's not a recognized color! Though it would probably be the most challenging color/pattern combination to breed, bar none!

 

[judymac]

I have never had direct experience with combining Es and ej and don't really know how those would interact. The Es allele basically squishes all the agouti banding up to the top of the hairshaft, while the ej allele removes the black and silver bands and distributes those pigments onto different hairs; not sure how that would play out when you put them both on the same rabbit. @judymac may have some insight regarding that.

I have never bred steel, so I have no direct experience with this. But, Green Barn Farm has a page that shows how the different genotypes interact, including Es and ej, at A/E Gene Combinations

One thing I did notice was the extent of white in the front of the rabbit, including the ears. Generally, a broken should have color around the nose (spots on either side or a solid 'butterfly' above the nose), around both eyes, and on the ears. But this rabbit is a white-ear. No color I can see on the ear. I know some BEW VM (blue eyed white Vienna marked, with white often on the nose, a strip on the face, and toes, sometimes with a Dutch-looking white collar) have been selecting for this white ear trait, you may even see WE for 'white ear' on the pedigree.

 

[MsTemeraire]

Looking at the Continental Giants in USA Group's page Conti Standards – Continental Giant Rabbit it appears that the BRC recognizes Black, Dark Steel Grey, Light Steel Grey, Opal, Yellow, Chinchilla, 2 varieties of Agouti (Chestnut & Red), & 2 varieties of White (REW & BEW).
From the description on their color page Conti Colors – Continental Giant Rabbit I'm guessing that dark steel is STS and light steel is GTS,

STS isn't recognised in any breed under the BRC. Two shades of steel occur in steel breeding - one is like Agouti (Chestnut) without the ear lacing, nostrils, belly etc. This is light steel. Then there is Dark Steel which is much more of a dense black with tipping. The reason for the two shades isn't known but thought to be modifiers.

A friend just had a harlequin Dutch appear in one of her litters - she calls it her bumblebee bunny. It's so dramatic, we're wondering why it's not a recognized color! Though it would probably be the most challenging color/pattern combination to breed, bar none!

They're a recognised colour in Europe and the UK. In the latter they're treated as a separate breed - Tri-Colour Dutch (thank the Dutch rabbit breed club for that, and not recognising them as Dutch). They're a breed I've always loved, I had my first ones around 1979. I find them a bit easier to breed than 'normal' Dutch since the standard of markings is so high in normal Dutch that breeding a good one can be difficult. Whereas the pattern isn't so near perfect in Tri Dutch, so there's plenty of chance for better ones to appear (if that makes sense). I don't mind the challenging aspect since they are a breed that's a joy to own, being intelligent (one of the most intelligent there is), very people-focussed and friendly, full of character, and easy to find homes for as pets because of this.

 

[MsTemeraire]

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I think you have the White Ear gene here, causing roaning on the body, plus also possibly Vienna giving the extra white on the head.

 

[Alaska Satin]

STS isn't recognised in any breed under the BRC. Two shades of steel occur in steel breeding - one is like Agouti (Chestnut) without the ear lacing, nostrils, belly etc. This is light steel. Then there is Dark Steel which is much more of a dense black with tipping. The reason for the two shades isn't known but thought to be modifiers.

Yes, what I should have said is that the BRC colors dark and light steel read like they're describing American GTS and STS. In the American system, GTS generally looks like chestnut agouti with the "trim," to a greater or lesser extent depending on the breed, which makes sense since they're agoutis with a steel allele.

I remember from earlier discussions that the BRC doesn't keep a studbook, but do you know the genotypes of what the BRC calls dark and light steel? Are they both <A_B_C_D_Es_>, or is the dark <A_B_cchd_D_Es>, or are they something else entirely?

They're a recognised colour in Europe and the UK. In the latter they're treated as a separate breed - Tri-Colour Dutch (thank the Dutch rabbit breed club for that, and not recognising them as Dutch). They're a breed I've always loved, I had my first ones around 1979. I find them a bit easier to breed than 'normal' Dutch since the standard of markings is so high in normal Dutch that breeding a good one can be difficult. Whereas the pattern isn't so near perfect in Tri Dutch, so there's plenty of chance for better ones to appear (if that makes sense). I don't mind the challenging aspect since they are a breed that's a joy to own, being intelligent (one of the most intelligent there is), very people-focussed and friendly, full of character, and easy to find homes for as pets because of this.

According to my Dutch breeder friend, there used to be an ARBA COD (Certificate of Development) for a harlequin variety of Dutch, but they dropped it without completing it. Given the challenge of perfecting the harlie markings, even without the Dutch markings to contend with, I can imagine why.

In America, too, the quality of Dutch is so high that I can't imagine a tricolor being able to compete with the other colors for years or even decades. While my American brain thinks it's a little weird to have so many different varieites of Dutch compete as different breeds, I do see the wisdom of doing it that way for the harlequin Dutch.

 

[MsTemeraire]

I remember from earlier discussions that the BRC doesn't keep a studbook, but do you know the genotypes of what the BRC calls dark and light steel? Are they both <A_B_C_D_Es_>, or is the dark <A_B_cchd_D_Es>, or are they something else entirely?

Yes they are both A_B_C_D_Es_
Why two shades occur I don't know, but it's considered to be modifiers. This is the same in any breed which has Steel.

The exception is our UK Flemish Giant which is 'dark steel' but in fact is not steel at all, It was found to be a heavily modified agouti with a darkening modifier.

While my American brain thinks it's a little weird to have so many different varieites of Dutch compete as different breeds, I do see the wisdom of doing it that way for the harlequin Dutch.

It's only the Tri that's a separate breed. The 'normal' Dutch - black, blue. chocolate. yellow, brown-grey, steel, tort and pale-grey - are all the same breed. Lilac and Chinchilla are not recognised at all, not even as a COD and I've only ever seen one Chin Dutch in the UK which was imported, and not at a show.

 

[MsTemeraire]

In America, too, the quality of Dutch is so high that I can't imagine a tricolor being able to compete with the other colors for years or even decades.

They are considered the same breed in Europe, and do compete with other colours (and win!), but I have noticed Europe seems a little less fussy about the Harlequin pattern on them than we are. Their Dutch breed standard differs from ours (UK breed standard is more or less the same as USA since the US first imported the breed from the UK) and allows slightly higher weight (5.5lbs), a closed neck marking, and longer stops. The blaze is wider and the saddle allowed to be a tiny bit further back. There are also points for coat, which isn't a thing for normal Dutch.

Our Tri Dutch SOP is modelled on the European Dutch standard since they were imported from Europe (1960s). Which is all fine... until you get a judge who disregards the standard and thinks they should be exactly like a normal Dutch. And there are plenty who do that.

 

[user 8990]

Fascinating! Thanks to all who responded. This is complicated and I’m finally feeling as though I can wrap my brain around it!

Definitely White ear genetics in place as the sire is White eared. Heavy Vienna lines as well. I hadn’t realized how much roaning there would be with the White ears. So it’s not the cchd. Now the pedigree and genetics make sense!

So can Es hide in a self pedigree? How about agouti?

 

[MsTemeraire]

So can Es hide in a self pedigree?

It certainly can.
aa E(s)_ appears self black.
A_ E(s)E(s) appears self black ("supersteel") (and by logic, aa E(s)E(s) will, too).
A_ E(s)e also appears self black.

How about agouti?

That's one thing which can't hide steel. If you're looking to breed out Steel, keep the agoutis.