Genetics Qs- sex link, egg color

[nicalandia]

I can't follow this logic.

It's quite hard to follow indeed.

All you need for Autosexing is e+ and sex linked barring, any other pattern genes Like Pg, Mo, Ml, Co, Db have no effect on the sexing. Unless its recessive white I would no worry about it

 

[DarJones]

"If I cross two brown Leghorns that both carry so many recessive genes wouldn't a lot of the offspring by chance get some from both parents and then express them?
I can't follow this logic."

No, they wouldn't show up in a brown leghorn x brown leghorn cross. Brown leghorns are stable for dominant genes that cover the recessives. I've only seen one recessive show up in a brown leghorn x brown leghorn cross and it was for paler colored feathers, i.e. not normal brown. Cross a brown leghorn X another breed with different stable genetics and - depending on the genetics - the recessives can show up in the F2 or F3 generation. This is how I got a yellow hen with speckles.

Let me try it this way and see if it makes more sense. Brown leghorns are homozygous for genes that produce brown feathers, penciling/partridge, and mahogany (seen mostly on the roosters). Behind the brown feathers are recessive genes that produce an orange/brown feather, yellow feathers, and paler brown breast feather colors. The only way to see the recessives is by crossing to a different breed that does not carry overriding dominant genes. You might think crossing a brown leghorn X white leghorn would show the recessives. It probably wouldn't depending on which gene the white leghorn carries, for example dominant white covers up just about everything else. This is because brown leghorns and white leghorns are relatively closely related and carry many of the same genes. Make a cross with an entirely different breed and the recessives have a very good chance of showing up. My cross with Silver Laced Wyandottes was very effective at showing the recessives.

Nicalandia, If I hadn't made the crosses and seen the results, I would not have posted. Note that the question was not just about autosexing, but also about egg color, how to breed an autosexing green egg layer. Since you toss in barring, remember that it needs slow feathering. combine E+ with Barring with Slow feathering plus oocyanin on chromosome 1 plus either straight comb or rose comb from chromosome 7 plus porphyrin biopath (either turned on or turned off) plus white eggs from both brown leghorn and legbars, and you have a recipe for several years of breeding to stabilize the traits. However, this was not my point. My point was that each additional breed introduced into a cross brings a set of recessives that may have to be sorted out to stabilize the new breed. Two breeds are messy. Three or four breeds used in a cross may bring so many diverse recessives into the mix that stabilizing anything would take more years than most of us have to work with a new breed. Note that Moonshiner's first reply in this thread involved using Legbars (blue eggs), Bielefelders (brown eggs), Brown Leghorn's (white eggs), and Welsummers (dark brown eggs).

 

[The Moonshiner]

"If I cross two brown Leghorns that both carry so many recessive genes wouldn't a lot of the offspring by chance get some from both parents and then express them?
I can't follow this logic."

No, they wouldn't show up in a brown leghorn x brown leghorn cross. Brown leghorns are stable for dominant genes that cover the recessives. I've only seen one recessive show up in a brown leghorn x brown leghorn cross and it was for paler colored feathers, i.e. not normal brown. Cross a brown leghorn X another breed with different stable genetics and - depending on the genetics - the recessives can show up in the F2 or F3 generation. This is how I got a yellow hen with speckles.

Let me try it this way and see if it makes more sense. Brown leghorns are homozygous for genes that produce brown feathers, penciling/partridge, and mahogany (seen mostly on the roosters). Behind the brown feathers are recessive genes that produce an orange/brown feather, yellow feathers, and paler brown breast feather colors. The only way to see the recessives is by crossing to a different breed that does not carry overriding dominant genes. You might think crossing a brown leghorn X white leghorn would show the recessives. It probably wouldn't depending on which gene the white leghorn carries, for example dominant white covers up just about everything else. This is because brown leghorns and white leghorns are relatively closely related and carry many of the same genes. Make a cross with an entirely different breed and the recessives have a very good chance of showing up. My cross with Silver Laced Wyandottes was very effective at showing the recessives.

Nicalandia, If I hadn't made the crosses and seen the results, I would not have posted. Note that the question was not just about autosexing, but also about egg color, how to breed an autosexing green egg layer. Since you toss in barring, remember that it needs slow feathering. combine E+ with Barring with Slow feathering plus oocyanin on chromosome 1 plus either straight comb or rose comb from chromosome 7 plus porphyrin biopath from brown leghorn plus white eggs from using legbars, and you have a recipe for several years of breeding to stabilize the traits. However, this was not my point. My point was that each additional breed introduced into a cross brings a set of recessives that may have to be sorted out to stabilize the new breed. Two breeds are messy. Three or four breeds used in a cross may bring so many diverse recessives into the mix that stabilizing anything would take more years than most of us have to work with a new breed.

Are you talking dark brown Leghorns?
I was talking light browns.
What I'm not getting is this whole hiding recessive genes that will then show up and become a problem. And I'm talking about pattern only as in reference to making it auto sexing.
This post you bring up slow feathering. Why? And it doesn't have to be slow feathering. Everything ive done is with fast feathering.
I have experience with it brown leghorn crossed with legbars, leghorn Xs welsummer, leghorn Xs Welbar and leghorn crosses. None have had anything recessive pop up and cause an issue.
Use leghorns as an example since ive done a lot with them. What are these recessive genes and what are the genes that hide each?

 

[JacinLarkwell]

I gotta agree. If a breed has a bunch of recessive genes just floating around, they're bound to pop up in pure breeding. It's just basic 6th grade genetics.

Also what type of green were you looking for? Light or dark? Both those colors require different browns introduced

 

[DarJones]

We all have something to learn from each other. Keep this in mind, I'm not trying to say I know even a good smattering about chicken genetics. I know what I have experienced which includes keeping light brown leghorns, the blue egg laying brown leghorns developed by Bramwell at UARK, Silver Laced Wyandottes, Dominiques, Barred Rocks, Black Australorps, Sebrights, Ameraucanas, and a few other breeds over the years.

The only crosses that I have made and spent significant time studying the background genetics is the Silver Laced Wyandotte X blue egg laying Brown Leghorns. I made plenty of other crosses, but did not grow out hundreds of offspring to see the segregating genes. I have grown out about a thousand chicks from the SLW X BEBL cross and am growing another 300 or so this year.

Here are descriptions of the phenotypes of birds that I saw segregate out:

1. There was one hen that was yellow with speckles. I know the mother of that hen and am certain the yellow color originated from the brown leghorn grandparent. I only saw the one single hen with this coloring.
2. There were several birds that had orange/brown feather color. This is very different from the normal brown color of Brown Leghorns. The best way I can describe it is to look at a really well colored brown leghorn rooster at the neck and hackle area where they often have orange feathers.
3. Mahogany red is hiding behind the brown feathers. If it shows up, it is usually on roosters on or around the wings. Look at some of your roosters and see if they show evidence of carrying mahogany. This picture has a rooster with red wings that segregated from the cross. http://www.selectedplants.com/miscan/2018chickens10.jpg
4. Penciling/partridge is carried by Brown Leghorns. It is mostly hidden behind the brown coloring, but if you look closely at the feathers on the chest and near the tail you can see the speckling effect. Look closely at the rump and tail feathers on these hens to see the effect of penciling. http://www.selectedplants.com/miscan/slw.blue1.jpg
5. Puff feathers near the tail are common in Brown Leghorn. I don't want them on my birds. These are small puffy feathers just in front of the main tail feathers. This is caused by a recessive based on the crosses I made.
6. Weak chick legs showed up in Brown Leghorns This can be made worse by too high temperature in an incubator. Most of what I got was curled toes and sometimes legs that would not support a chick. I have not seen a case of curled toes in the last 3 years so must have gotten this gene pretty well suppressed.
7. I had one rumpless hen in 2018. Since rumpless is sometimes a hidden recessive in blue egg layers, it is likely this was brought in from the blue egg laying brown leghorns. This is not likely to be in a normal strain of brown leghorns.

If a breed has a bunch of recessive genes just floating around, they're bound to pop up in pure breeding. It's just basic 6th grade genetics.

No, they don't have to pop up. If a dominant gene is homozygous in a breed and covers a recessive, the recessive literally never shows up until a cross is made to a breed that does not have that dominant gene. Consider dominant white. You have certainly seen what happens when dominant white is crossed to just about any other breed. What do you get in the F2?

 

[NatJ]

Since you toss in barring, remember that it needs slow feathering.

For autosexing, no you do not need slow feathering. You just need the barring gene, and your birds might look "cuckoo" instead of "barred."

Slow feathering can help make nice clear bars on the chickens, which is nice for Barred Rocks in a show, but does not help with the autosexing.

 

[Feathercrazie]

So if all these breeds carry all these recessive genes why don't they show up constantly when breeding within the breed?
If I cross two brown Leghorns that both carry so many recessive genes wouldn't a lot of the offspring by chance get some from both parents and then express them?
I can't follow this logic.

They do. This is why many breeders of birds for show keep records of every bird hatched and cull sharply. Line breeding (inbreeding) helps with this, but must be done with great care as you can quickly lose vitality with inbreeding. And you must cull viciously.

 

[Feathercrazie]

For autosexing, no you do not need slow feathering. You just need the barring gene, and your birds might look "cuckoo" instead of "barred."

Slow feathering can help make nice clear bars on the chickens, which is nice for Barred Rocks in a show, but does not help with the autosexing.

With autosexing you are only concerned with the color of the chicks at hatch. If you are breeding for show birds the color at hatch gives you some clues but not enough to say which ones will be the "correct" color.

 

[The Moonshiner]

They do. This is why many breeders of birds for show keep records of every bird hatched and cull sharply. Line breeding (inbreeding) helps with this, but must be done with great care as you can quickly lose vitality with inbreeding. And you must cull viciously.

Are you a breeder? Is this from experience?
I've done a lot breeder. Sometimes to show and sometimes for other reasons.
That is not experience besides a few breeds that are known to produce "sports" such as recessive whites.

 

[RoostersAreAwesome]

We all have something to learn from each other. Keep this in mind, I'm not trying to say I know even a good smattering about chicken genetics. I know what I have experienced which includes keeping light brown leghorns, the blue egg laying brown leghorns developed by Bramwell at UARK, Silver Laced Wyandottes, Dominiques, Barred Rocks, Black Australorps, Sebrights, Ameraucanas, and a few other breeds over the years.

The only crosses that I have made and spent significant time studying the background genetics is the Silver Laced Wyandotte X blue egg laying Brown Leghorns. I made plenty of other crosses, but did not grow out hundreds of offspring to see the segregating genes. I have grown out about a thousand chicks from the SLW X BEBL cross and am growing another 300 or so this year.

Here are descriptions of the phenotypes of birds that I saw segregate out:

1. There was one hen that was yellow with speckles. I know the mother of that hen and am certain the yellow color originated from the brown leghorn grandparent. I only saw the one single hen with this coloring.
2. There were several birds that had orange/brown feather color. This is very different from the normal brown color of Brown Leghorns. The best way I can describe it is to look at a really well colored brown leghorn rooster at the neck and hackle area where they often have orange feathers.
3. Mahogany red is hiding behind the brown feathers. If it shows up, it is usually on roosters on or around the wings. Look at some of your roosters and see if they show evidence of carrying mahogany. This picture has a rooster with red wings that segregated from the cross. http://www.selectedplants.com/miscan/2018chickens10.jpg
4. Penciling/partridge is carried by Brown Leghorns. It is mostly hidden behind the brown coloring, but if you look closely at the feathers on the chest and near the tail you can see the speckling effect. Look closely at the rump and tail feathers on these hens to see the effect of penciling. http://www.selectedplants.com/miscan/slw.blue1.jpg
5. Puff feathers near the tail are common in Brown Leghorn. I don't want them on my birds. These are small puffy feathers just in front of the main tail feathers. This is caused by a recessive based on the crosses I made.
6. Weak chick legs showed up in Brown Leghorns This can be made worse by too high temperature in an incubator. Most of what I got was curled toes and sometimes legs that would not support a chick. I have not seen a case of curled toes in the last 3 years so must have gotten this gene pretty well suppressed.
7. I had one rumpless hen in 2018. Since rumpless is sometimes a hidden recessive in blue egg layers, it is likely this was brought in from the blue egg laying brown leghorns. This is not likely to be in a normal strain of brown leghorns.


No, they don't have to pop up. If a dominant gene is homozygous in a breed and covers a recessive, the recessive literally never shows up until a cross is made to a breed that does not have that dominant gene. Consider dominant white. You have certainly seen what happens when dominant white is crossed to just about any other breed. What do you get in the F2?

Do you have a picture of the yellow hen?

I’m not seeing anything in the pictures that leghorns don’t already have. It looks to me like the normal results of mixing two distinctly different patterns. Brown leghorn roosters already have that red, though it looks more excessive in the crossed rooster likely due to the columbian of the wyandottes. That patterning you call penciling is already visible in leghorns, as you mentioned, so it isn’t a recessive trait that only popped up in the cross. It may have been exaggerated in the cross, but that’s due to other genes interacting with it, not the lack of dominant genes. The tail cushion, again, already is a trait that isn’t hidden in brown leghorns, which means that it doesn’t only appear when you mix breeds. Rumplessness does sound like a recessive trait, but it’s likely very uncommon, and does pop up in purebred leghorns (I’ve seen a couple of them with it).