Red Laced Cornish X and project talk (pics p. 8)

[AquaEyes]

Quote:
Actually, the odds are 2 out of 3 that "he's a carrier" if he's the offspring of two heterozygous parents.

How do you figure???

Hh x Hh = (according to punnet squares) 25% HH, 50% Hh, 25% hh

How do you get 1/3 of a mating?

Now keep in mind, I'm not up to par on my chicken colors and combinations.. but according to basic genetic principles, my punnet squares make sense...

Saying something is 1/4 means you have one chance out of four possibilities. When you remove a possibility, now you have 1/3.

SO....in a standard hybrid cross like you posted above, there is a 1/4 chance of getting a homozygous recessive, which will look different from the other 3/4. If your bird doesn't look like the homozygous recessive, then you've just removed a possibility. Now you put 3 in the denominator instead of 4. So, of the 3 that are NOT homozygous recessive, you would have 2/3 that are heterozygous, and 1/3 that is homozygous dominant.

ETA -- if you look on breeder websites for all sorts of animals with mutations being captive bred, you'll find the "2/3 chance split to...." to be very common. It's just as I explained. In a Hh X Hh cross involving a recessive trait and a complete dominant trait, you get only two phenotypes -- recessive and dominant. Recessive phenotype will be 1/4. Dominant phenotype will be 3/4, and of those 3 that look the same, 2 will be heterozygous and 1 will not. That's how you get 2/3.

 

[SteveH]

Quote:
How do you figure???

Hh x Hh = (according to punnet squares) 25% HH, 50% Hh, 25% hh

How do you get 1/3 of a mating?

Now keep in mind, I'm not up to par on my chicken colors and combinations.. but according to basic genetic principles, my punnet squares make sense...

Saying something is 1/4 means you have one chance out of four possibilities. When you remove a possibility, now you have 1/3.

SO....in a standard dihybrid cross like you posted above, there is a 1/4 chance of getting a homozygous recessive, which will look different from the other 3/4. If your bird doesn't look like the homozygous recessive, then you've just removed a possibility. Now you put 3 in the denominator instead of 4. So, of the 3 that are NOT homozygous recessive, you would have 2/3 that are heterozygous, and 1/3 that is homozygous dominant.

ETA -- if you look on breeder websites for all sorts of animals with mutations being captive bred, you'll find the "2/3 chance split to...." to be very common. It's just as I explained. In a Hh X Hh cross involving a recessive trait and a complete dominant trait, you get only two phenotypes -- recessive and dominant. Recessive phenotype will be 1/4. Dominant phenotype will be 3/4, and of those 3 that look the same, 2 will be heterozygous and 1 will not. That's how you get 2/3.

Sorry, I have to side with kfacres. Of the dark chicks in the F2s, there's a 50% chance of any one of them carrying one copy for recessive white. We already know it's not pure white recesive

so that's out of the equation. It's one of the 75% hatched not white, so is one of the remaining that are either carrying one copy or no copy of recessive white. [50/50 chance either way, not 33 1/3 to 66 2/3 against]

 

[AquaEyes]

Quote:
Saying something is 1/4 means you have one chance out of four possibilities. When you remove a possibility, now you have 1/3.

SO....in a standard dihybrid cross like you posted above, there is a 1/4 chance of getting a homozygous recessive, which will look different from the other 3/4. If your bird doesn't look like the homozygous recessive, then you've just removed a possibility. Now you put 3 in the denominator instead of 4. So, of the 3 that are NOT homozygous recessive, you would have 2/3 that are heterozygous, and 1/3 that is homozygous dominant.

ETA -- if you look on breeder websites for all sorts of animals with mutations being captive bred, you'll find the "2/3 chance split to...." to be very common. It's just as I explained. In a Hh X Hh cross involving a recessive trait and a complete dominant trait, you get only two phenotypes -- recessive and dominant. Recessive phenotype will be 1/4. Dominant phenotype will be 3/4, and of those 3 that look the same, 2 will be heterozygous and 1 will not. That's how you get 2/3.

Sorry, I have to side with kfacres. Of the dark chicks in the F2s, there's a 50% chance of any one of them carrying one copy for recessive white. We already know it's not pure white recesive

so that's out of the equation. It's one of the 75% hatched not white, so is one of the remaining that are either carrying one copy or no copy of recessive white. [50/50 chance either way, not 33 1/3 to 66 2/3 against]

Whoops, I typed "dihybrid" instead of "hybrid." I'll fix that in my previous post. But the rest of what I said was correct.

Hh X Hh = HH, Hh, Hh, and hh.

1/4 are HH
2/4 are HH
1/4 are hh

HH and Hh appear dark, hh appears white.

Am I correct so far?

If so...then 3/4 will appear dark, and 1/4 will appear white.

If you're looking at a dark chick, we know immediately that it is not white, thus we remove hh as a possibility. Thus we are concerned only with the other options, and our new "100%" will deal with only HH and Hh. Statistically, there will be twice as many Hh as there are HH, though they both look the same.

Here's some algebra. HH = X, and since there are twice as many Hh as there are HH, then Hh = 2x. X + 2x = 100%. Thus when looking at a dark bird from a Hh X Hh cross, you will have a 2 out of 3 chance that it is Hh.

 

[kfacres]

We are all 3 correct, it's just that we looked at it a different way... I looked at the chick as being part of a entire batch of hatchlings, and the fact that he would be either in the 50% that has the recessive gene, or the 25% that does not...

You looked at it as the single chick alone, in the fact that you automatically excluded the recessive gene, obviously doesn't have that; which is also the correct way in doing so.

I have never seen anyone promote the 1/3. 2/3 ordeal, I guess that I always assume, that it's a given that they don't show it...

Makes sense to me, guess your way is better.. bumps my odds up to 66% instead of 50!

 

[AquaEyes]

Quote:
Yes, it is correct to say that 1/2 of the chicks of Hh X Hh will be Hh, but if you have a dark chick in your hand, that dark chick has a 2/3 chance of being Hh. And that was how the original statement was phrased.

I'm not trying to be difficult -- just improving your odds.

 

[pepper48_98]

How do you tell what gene the chick parent stock or the chick has. I read about all the different combinations but is there a way that one can know without sending a sample out for a DNA test?

 

[pepper48_98]

Right now I have a WLR roo over a dark hens. I just had 20 atch and only have about 5 darks. The rest will be either jublie or WLR and if I am lucky, a few whites. Another 18 should be hatching Saturday from the same pens.

 

[SteveH]

Actually I was entirely wrong. I submitted that post, instantly realized it was wrong, but had to hit the road. {I missed two closeing times, [due to leaving late and being given a wrong address], had to pay more for groceries, only got half of stuff I went for, and just put the groceries away.} After making the crack about the visually whites being out of the picture, I put them right back in. The colored chicks carrying recessive white will out number those not by a margin of 2 to 1............................ in other words, 2/3rds are carrying recessive white.

However, Jody, the wlrs you bought from me carry only one copy of dominate white. The dark feathers on the one I kept might be black bleeding through the white lace.

 

[SteveH]

Quote:
Test breeding.

Actually that's not a very complete answer, experienced breeders are studying the color of down and pattern on chicks and relating that to their genotypes [the color genes they carry], plus carefully studying the pattern and colors of adults. I'm only starting to learn the proper colors anyway, but for show purposes I would absolutely have to know what the color and pattern looks like for a variety....................... if I show up at a show with a WLRC that is double laced or mutilaced, it's going to get the gate. Same would be true of showing up with a DC that is single laced black over red instead of double laced........................ the judges would know its not a pure DC.

 

[SteveH]

Quote:
If the three varieties [DCs, WLRCs, and WCs] have been mixed back and forth, patterns and colors may be mixed to the point where few chicks will meet the APA's description for any one of the varieties. Doesn't affect their quality as a meat bird, but they can't be shown successfully.