Definining Blue, Lavander, Lilac And Cream In Sebastopols.

[pete55]

DEFININING BLUE, LAVANDER, LILAC AND CREAM IN SEBASTOPOLS.

Hi All

Further to a previous paper on genetics for colour and pattern I have looked at the genetics controlling the more unusual colours of Sebastopols that are being developed in the USA. As I have said previously I may be incorrect but I hope this work continues to add to the overall knowledge base. Once again I am indebted to my friends on the Sebastopol Geese Lovers Forum for their continued support and kind permission to use photographs of their lovely birds. In particular my thanks to Vicky, Christine, Kim and Barb.

Pete

There certainly seems to be some confusion around defining what Lilacs, Lavanders and Creams look like! There's been some debate on another forum of what a Lavander is!!! This is an area that URGENTLY needs clarification. As more breeders produce Sebastopols in colours of Blue, Lilac, Lavander and Cream then these will need defining. The visual colour of the goose is an expression of the interaction of its genes that are responsible for colour. Its appearance is called its Phenotype. The genetic code for the interaction of the genes is called its Genotype. It is here that lies the potential for great confusion and to resolve this dilemma the bird's Phenotype must correspond with its Genotype

Some maintain that a Lavander is the result of interaction between Blue and Buff genes while other opinions are that lavander is the interaction of Blue genes only. To clarify the matter I wrote to Dave Holderresad and recieved the following reply;

"Lavender is the interaction of 2 different loci; Blue is the result of a single locus and Gray is the foundation color."

The statement is slightly ambiguous but I will try to explain it. However this is MY interpretation and I may be incorrect. Basically the genes for colour are found in pairs. An allele is simply a single variation of this gene and occupies a certain position (or locus) on that gene. In this case we are discussing the Blue gene (often coded as Bl) and this is referred to as autosomal gene which exhibitis partial dominance. Put more simply it is not a sex linked gene and the incomplete dominance means it can produce two levels of Blue colour.

The statement was; "Lavender is the interaction of 2 different loci; Blue is the result of a single locus and Gray is the foundation color."

So interpreting this statement it is saying that a Blue results from a single allele at one position (locus). Therefore the foundation colour of Grey has one partially dominant allele for Blue and its genotype would be written as; Bl, bl. The single partially dominant allele (Bl - written as a capital to represent dominance) changes the grey goose to a visual Blue. It is said to be Heterozygous for the Blue gene (meaning it has 2 different alleles - Bl and bl).

A Blue and a Grey Sebastopol owned by Barb (Sebastopol Geese Lovers Forum)

Now if the grey goose inherited a Blue gene from each parent then it would be Homozygous for the Blue gene and its genetic code for blue could be written as Bl, Bl. It has a pair of Blue genes. One allele occupying a locus on a gene from the father and one allele occupying a locus on a gene inherited from the mother. As the bird has a pair of Blue genes then the full visual effect of the Blue gene is realised and the bird appears as an even lighter blue.

Think of it as; if one blue gene changes a Grey bird to a visual Blue, then the effect of an additional Blue gene changes a Blue bird to an even lighter colour sometimes refered to as a Silver (or is this Lavander)!

There's no easy way to explain it and as yet it is not certain what the genotype for a Lavender is. Is it the result of the bird being homozygous for the Blue gene or does the statement from Holderreads mean that Lavander is the result of Blue and Buff genes from different loci. Unfortunately the statement is not clear enough for me to make a decision and I have asked for further clarity. However in personal communication with another goose breeder they confirmed that Holderreads had e-mailed the following statement; "Matings of Blue x Blue or Blue x Lavender typically result in offspring of both Blue and Lavender. Lavender x Lavender results in Lavender offspring." There is no mention that Lavanders are the result of intereaction with Blue and Buff genes.

SILVERS OR ?LAVANDERS
So having established that there are two levels of Blue what on earth do people call the bird with the palest colour (which is homozygous for Blue). Is this a Silver or is this the elusive Lavander??? If a breeder mates 2 'pure' Blue Sebastopols together then this breeding should produce the following;

Silver male x 1 (visually lighter blue)
Blue males x 2
Grey male x1
Silver female x 1 (visually lighter blue)
Blue females x 2
Grey female x1

So my question is has anybody done this cross and produced these lighter blue birds? If so; what are they called???

If these pale blue birds which are (homozygous for the Blue gene) are then 'test' mated together then they will also only produce the same pale blue birds. So IF we are calling these pale Blue birds Lavanders then;

Lavander x Lavander = 100% Lavander

A pair of Lavander Sebastopols. Bred by Dave Holderread and owned by Cottage Rose Sebastopols.

BUFF
The Buff gene is known as a recessive sex linked gene. This means that it is carried on the Z sex chromosome. In order to show visually all the bird’s Z chromosomes must carry a recessive form (allele) of this gene. So in the case of a female whose genotype for sex is ZW then only one recessive gene that is linked to the Z chromosome is required for the effect to be expressed visually. In the case of a male with two Z chromosomes then both genes must carry the recessive gene for the effect to show visually. If only one of the Z chromosomes carries a recessive gene then the male will carry (or be ‘split’ for) the recessive gene in its genotype but its phenotype remains the same. The following matings show how to produce Buffs.

Grey male x Buff female = 100% Grey but all Males are split for Buff.
Grey male (split for Buff) x Grey female = 25% Grey males (split for buff), 25% Grey males, 25% Grey females, 25% Buff females.
Grey male (split for Buff) x Buff female = 25% Grey males (split for buff), 25% Buff males, 25% Grey females, 25% Buff females.
Buff male x Grey female = 50% Grey males (split for Buff) and 50% Buff females.
Buff male x Buff female = 100% Buff

A Buff daughter with Grey mother owned by Zanter (Sebastopol Geese Lovers Forum)

LILACS
Using the information already discussed about the Blue and Buff genes we can use this information to predict the appearance of the Goose when these genes interact together. All that needs to be remembers is that Blue is a partially dominant gene and Buff is a sex linked recessive gene. Therefore;

Blue male x Buff female = 50% Blue and 50% Grey (all males are split for Buff)
Buff male x Blue female = 25% Blue males (split for Buff), 25% Grey males (split for Buff), 25% Buff female, 25% Lilac female.
Blue male (split for Buff) x Buff female = 25% Blue, 25% Grey, 25% Buff, 25% Lilac (in equal sex ratios) (all males are split Buff).
Lilac male x Buff female = 50% Lilacs and Buffs (all in equal sex ratios)
Lilac male x Lilac female = 25% Buff, 50% Lilac, 25% Cream (all in equal sex ratios)

The final mating of Lilac to Lilac gives the parents genes the opporunity to interact and the result is 25% of the offspring have 2 Blue genes. They have a double dose of the Blue gene (Homozygous) but also have the Buff gene. If we recall the information on the Lavander it is a lighter shade of Blue due to being homozygous for the Blue gene. In effect the goose is a Lavander combined with the visual effect of Buff.

A rare Lilac Sebastopol owned by Cottage Rose Sebastopols.

CREAM
We have seen that a Cream should appear visually as an even lighter shade of Lilac due to the presence of the additional Blue gene. Unfortunately I have not seen a Cream Goose or even a picture but would imagine it is a very attractive pale mushroom colour. If the Creams are used in the breeding programme then the following matings will produce Creams;

Lilac male x Lilac female = 25% Buff, 50% Lilac, 25% Cream (all in equal sex ratios)
Cream male x Lilac female = 50% Lilacs and 50% Cream
Lilac male x Cream female = 50% Lilacs and 50% Cream
Cream male x cream female = 100% Cream
Lavander male (split for Buff) x Lavander female = 25% Lavander males (split for Buff), 25% Lavander males, 25% Lavander females, 25% Cream females
Cream male x Blue female = 25% Blue males (split for Buff), 25% Lavander males (split for Buff), 25% Lilac females, 25% Cream females

SUMMARY
From the information above it would be my proposals to classify the Sebastopol colours that are a result of interaction between the Blue and Buff gene(s) as follows;

Blue - a visually Blue bird which has a single Blue gene (heterozygous for Blue).
Lavander - a visually pale Blue bird which has a pair of Blue genes (homozygous for Blue)
Lilac Male - a visually Buff bird with Blue overlay. Has a single Blue gene (heterozygous for Blue) and a pair of Buff genes (homozygous for Buff).
Lilac female - a visually Buff bird with Blue overlay. Has a single Blue gene (heterozygous for Blue) and a single Buff gene (heterozygous for Buff).
Cream Male - a visually Buff bird with Pale Blue overlay. Has a pair of Blue genes (homozygous for Blue) and a pair of Buff genes (homozygous for Buff).
Cream Female - a visually Buff bird with Pale Blue overlay. Has a pair of Blue genes (homozygous for Blue) and a single Buff gene (heterozygous for Buff).

Although some readers may find it complex to understand and first I hope this report clarifies some of the more unusual Sebastopol colours and enables others to forward their breeding programmes in these very attractive colours.

 

[Cottage Rose]

This is a wealth of information regarding a confusing topic for many of us.

Hats off to Pete for taking time out of his very busy life to research,
compile and share this information with us.
You are awesome!!!

 

[CelticOaksFarm]

That is fantastic information, thank you so very much for taking the time to do this.


Shellie

 

[Oregon Blues]

If it helps, the gene you are calling "blue" isn't blue, it is a dilution gene. It "fades" the color.

Blue is a dilution of Black. One dilution makes the color blue, two dilution genes make the color of splash, which is light silver in color, also called self blue in some breeds.

In geese, unlike any other species of animal, the dilution is on buff, to make the color "blue" which isn't anywhere near blue in color. It is a slightly blue tinted gray. If you get two dilutions on buff, you get "lavender" which is a light gray color. Also called silver.

In my Swedish Blue ducks, the lavenders (also called silver) have a brown gene. The lavender ducklings are cocoa colored as hatchlings and fade to a very light silver gray. In Swedish ducks, the splash (or self blue) ducklings are born splotched with silver and end up very light silver, almost white.

Because there is no black gene in geese, there is no true "blue" color. Geese called "Blue" are not blue. They are brown tinged gray. I've got a dark slate colored gosling right now, but dark as it is, it is a very different color from my blue ducks.

So, it depends upon whether you are talking about geese or about any other animal what you mean when you say blue. With every other animal, blue is a dilution of black.

 

[pete55]

Hi Oregon Blues

Thanks for adding your points to this discussion. I cannot get my head round all the points you have mentioned but can agree that the Blue gene is not strictly a 'colour' gene but the appearence gives the birds a 'blueish' appearence which owners can relate to. In the strictest sense it is a 'Diluting' gene but with geese there is another gene (or alelle) which produces a similar effect and is also sometimes referred to as 'the Diluting' gene. Also calling the 'Blue' gene a Diluting gene could lead to confusion as the effects of each are different. However in your discussion I believe you are referring to the Blue gene but I'm not sure what you meant by;

In geese, unlike any other species of animal, the dilution is on buff, to make the color "blue" which isn't anywhere near blue in color. It is a slightly blue tinted gray. If you get two dilutions on buff, you get "lavender" which is a light gray color. Also called silver.

The Buff gene is sex-linked to the male chromosome whereas the 'Blue' gene is independent of the sex chromosome (autosomal). In my opinion two dilutions of the Blue gene on a Buff goose will produce a visual Cream.

In the UK Cat Fancy the Blue gene is referred to as the 'Dilution' gene and does indeed dilute the appearance of Black cat to a shade of blue. However it will also change a Sealpoint (dark brown) to a Bluepoint and a Chocolatepoint to a Lilac. The effects are similar but the description of the colours is subjective until formally recognised by the responsible body for the hobby.


In a previous thread on genetics I have discussed the effects of the four gene pairs (allelles) responsible for all colours and patterns.

https://www.backyardchickens.com/forum/viewtopic.php?id=561779

In that thread I discussed the other gene responsible for dilution of colours.

At this point three of the genes responsible for colour and pattern have been examined. However the final gene for Dilution can cause more complications. The Dilution gene (Sd) is like the Blue gene (Bl) in that its visual effects are incompletely dominant but it is also sex linked to the Z chromosome. Therefore if a grey female inherited the Dilution gene in its dominant form (Sd) then the visual effect would be a dilute grey often with white markings around the base of the beak. If a male inherited a single dominant dilution gene it also appears visually as a dilute grey. However if it inherits a double dose of the dilution gene in its dominant form then the visual effect is White. This effect is known as being Dimorphic, meaning the birds can be visually sexed by their colour. Males will be white and females a dilute grey and it is this gene that is responsible for the Pilgrim breed. In a single dominant dose it dilutes the colour and in its double dominant form the effect is strengthened and the bird appears visually White.



Where the Dilution gene becomes very complicated is when it is combined with the recessive form of the Spotting gene. If a male has one dominant dilution gene and one recessive Spotting gene then the bird will be visually Dilute but split for Pied. If a female has a dominant dilution gene and a recessive spotting gene linked to her Z chromosome then the bird is visually White. If a male inherits a double dose of the Dilution gene in its dominant form and a single recessive Spotting gene then it remains a Dimorphic White but split for pied. If the dominant pair of Dilution genes are combined with a pair of recessive Spotting genes then the male is visually White. It appears confusing but as both the Dilution and Spotting gene are both sex linked then it can be said that the bird is a visual pure White when all Z chromosomes carry the dominant Dilution gene and the recessive Spotting gene. In fact this is the reason white Sebastopols can be sexed at hatching. As the baby males have a pair of Z chromosomes then the dilution effect is stronger and their down appears paler than the females.

Where this combination becomes more confusing is that a genetically White bird can have its other Blue and Buff genes masked. The bird may also be genetically Buff or Blue but the visual effect is hidden by the dominant effect of the Dilution gene. As an example the following is a genotype of a visually White male that is also Lilac; Z Z Sd Sd sp sp Bl bl g g.

A Dilute African Gander. The 'colour' being the result of inheriting a single Dilution Gene (note the white mask due to incomplete dominance).


I hope this clears any confusion and adds further to the discussion.

Pete

 

[banter]

Pete,
Can't thank you enough for the wealth of information!
It will help those of us breeding Sebastopols (both colors AND white to colors) to establish a better breeding plan! I hope that those of you who are breeding Sebs
( let's include those who are allowing their geese to lay and hatch etc. also!) , to keep records of the parents (a pedigree). It's very easy to make a photographic one in our age
of technology! I have several generations now, and I send a pedigree with any gosling/adult I sell. Many of us that are raising Sebs are doing this also. Sure helps deciding pairings down the line!

Banter/Zanter

 

[pete55]

Thanks Zanter

I think it's a very good idea to keep 'pedigrees' and/or breeding records as the new developments in coloured and patterned Sebastopols can be complex. Everybody should record the outcomes of their matings and in this way genetic theories can be fully tested. It is also good that other members debate and discuss their observations and opinions so the knowledge base is expanded further.

With the Dewlap Toulouse that we keep here it's hard enough keeping good records for both breeding lines and colours and we're only dealing with Greys and Buffs in this breed! (Although I have seen developmental whites and blues).

In fact while I'm writing this it occurred to me that in all the domestic breeds of geese I know the new developmental Sebastopols MAY have the widest range of patterns and colours to be found in domestic breed of geese. Credit of course must also go to Dave Holderread for his pioneering work in this breed with type and colour.

I've considered the Toulouse. Africans, Embdens, Romans, Steinbachers, Pomeranian, Shetland, Americans, Chinese etc and concluded that the above statement may be correct!!! The Sebastopols under development have their patterns result from all four sets (allelles) known to affect colour and patterns; Dilution Gene, Pied (Saddleback) Gene, Blue Gene and Buff Gene. Maybe other forum members can think of other breeds and help in this discussion

Now there's an interesting topic for discussion

Pete

 

[animaladdictions]

Oh my goodness! Is it just me or do you need a bachelors in genetics to understand this stuff?!

I hate to embarrass myself, but I just dont get any of this. Guess I need to go over it a few times. My hats off to all of you who understand it all. Pete... you always blow me away with your intelligence and ability to teach others. Now Im wondering what color my LaLa is! I thought Lavender. She/He (a Sebbie) is predominately white all over with a light blue/ grey covering her back, wings, and tail. The color isnt solid but is more like a splash and each feather has these striations of color sort of like a ....oh I dont know, a blue jean pattern? Its hard to know without seeing a pic I know (i cant post pics from my phone) but what does it sound like to you? Is this description a lavender splash? She hatched out looking like a typical light colored white Sebbie w/ orange feet and bill.

 

[pete55]

Hi Lisa

I would advise joining the Sebastopol Geese Lovers Forum. Im often on there and there's lots more pictures and Sebbie experts that will be able to pinpoint Lala's colour but he sounds like a Blue Splash to me

Im sorry the genetics is a bit high brow but its such an intersting topic for me and I sometimes get a bit carried away

On the forum I mentioned I've also simplifed things as tables for fast reference. Never think you embarass yourself as I enjoy the discussion and thats how we all share experience and knowledge. Goodness I laugh when I look back to when I was younger and 'green as grass'

I was lucky and my enthusiasm was spotted and I had a great friend and mentor who helped me along the way.

Best wishes

Pete

 

[Henk69]

Some believe that the spotting gene is not sexlinked but autosomal.
It is published as sexlinked, but never rectified.