Percentage of bloodline?

[AquaEyes]

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It is true that you can never gain the W chromosome from the breed whose genes you are trying to maximize if you use only pure-bred roosters to hybrid females, but in practice, gender is irrelevant in this breeding scheme -- you can just as easily use the pure-bred hens with the hybrid roosters.

And, in any case, if you continue on the mathematical formula, you'll continue to approach 100% but not get there. The W chromosome is very small, and relative to all the other chromosomes, contains a very tiny fraction of a percent of the active genes (which probably number around 10,000 or more for chickens). So if that's the only chromosome left from the first female, it'd account for something like 0.01 - 0.05% of the total number of genes.

 

[Henk69]

By only using roosters of breed A you would eliminate the Z chromosome of breed B immediately.

 

[saladin]

Quote:
It is true that you can never gain the W chromosome from the breed whose genes you are trying to maximize if you use only pure-bred roosters to hybrid females, but in practice, gender is irrelevant in this breeding scheme -- you can just as easily use the pure-bred hens with the hybrid roosters.

And, in any case, if you continue on the mathematical formula, you'll continue to approach 100% but not get there. The W chromosome is very small, and relative to all the other chromosomes, contains a very tiny fraction of a percent of the active genes (which probably number around 10,000 or more for chickens). So if that's the only chromosome left from the first female, it'd account for something like 0.01 - 0.05% of the total number of genes.

Another thought to add: Breeds of chickens are based on phenotype not genotype: though certainly the genotype plays a major role.

In a grading system the traditional way it has been done is by using various females with straight bred males.

 

[AquaEyes]

Yes, but I think the statement was that by never using hens of breed A, the W chromosome would always be from breed B.

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[saladin]

Yes, I understood that. What I'm saying is that it doesn't matter.

 

[AquaEyes]

Sorry, I was replying to Henk69. Yes, from a breed-standard standpoint, it matters only that the birds meet the standard and can reproduce their traits when paired to others that meet the standard. But "percentage of bloodline" goes deeper than "meeting a standard."

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[saladin]

 

[tls_ranch]

Wow, I didn't think a simple chart would create so much in depth genetics talk and debate

I just needed the chart to show a relative of mine a basic outline. But, I like to read about breeding and genetics and everyone's posts have been very interesting