Genetics question re: cinammon and pallid

[Jim]

I'm new to the forum and have a question about the interaction between cinammon and pallid genes. I have a blue cinammon female and have the opportunity to acquire a blue pallid male. My understanding is that the resulting offspring would be as follows:

Males - 100% Blue split for cinammon and pallid
Females - 100% Blue pallid

My question involves the males from this pairing. They have the cinammon gene on the X chromosome they got from mom and the pallid gene on the X chromosome they got from dad. Do these genes occupy the same locus or can they both be transmitted to any potential offspring?

It's not that I have some mad desire to have a houseful of blue cinammon pallids. Just curious about how it works. Any help would be appreciated.

Thanks
Jim

[gazz]

Maybe this will help you out it's a genetic calculator but it take some getting use to.For the breeding your planning to do this is the result it gave me.

males (blue/pallid cinnamon)
females (blue pallid)

So it's saying that the male offspring will be split pallid cinnamon.Not split pallid & cinnamon.So it say they will be blended not double slits.

Here the calculator it's set for ringnecks.
http://www.gencalc.com/gen/eng_genc.php?sp=0PsitIR

[Jay]

I'm new to the forum and have a question about the interaction between cinammon and pallid genes. I have a blue cinammon female and have the opportunity to acquire a blue pallid male. My understanding is that the resulting offspring would be as follows:

Males - 100% Blue split for cinammon and pallid
Females - 100% Blue pallid

Your resulting offspring prediction is correct.

My question involves the males from this pairing. They have the cinammon gene on the X chromosome they got from mom and the pallid gene on the X chromosome they got from dad. Do these genes occupy the same locus or can they both be transmitted to any potential offspring?

It's not that I have some mad desire to have a houseful of blue cinammon pallids. Just curious about how it works. Any help would be appreciated.

Both cinnamon and pallid genes occupy their respective loci since they are both primary mutations. Pallid is an allele of the Ino locus. But since the cinnamon locus and the Ino locus are located on the sex chromosomes, and males have two X chromosomes, it is possible for both genes to end up in one X chromosome through a process called genetic crossover. This phenomenon happens during reproductive cell division, AKA meiosis, that happens in the males' production of zygotes.

When mating a double split Cinnamon-Pallid to a Green hen for example, you are right that some of the resulting phenotype will be visual Cinnamon Pallids but since the crossover frequency between Cinnamon and Pallid is only 3%, then only 0.75% of the offsprings will be visual Cinnamon Pallids and they will all be hens. 0.75% will be cocks split to the Cinnamon-Pallid crossover.

Bear in mind that crossover also produces a specimen devoid of both Cinnamon and Pallid, hence, 1.5% of the offsprings will not contain any Cinnamon or Pallid genes.

Lastly, since Cinnamon and Pallid belong to their respective loci, they can then be inherited independent of each other in accordance with Mendel's Law of Independent Assortment. As such, pure Pallids and Cinnamons can also be produced. And depending on the type of linkage, they are generally produced at a much higher rate than the crossovers.

Let me know if you want me to clarify some more.

[Jay]

Maybe this will help you out it's a genetic calculator but it take some getting use to.For the breeding your planning to do this is the result it gave me.

males (blue/pallid cinnamon)
females (blue pallid)

So it's saying that the male offspring will be split pallid cinnamon.Not split pallid & cinnamon.So it say they will be blended not double slits.

Genotypically speaking, a Blue/Pallid Cinnamon is in fact a double split. Both you and Jim are correct. You just vary in semantics.

[Jim]

Got it. Thanks.

Where did you come up with the 3% crossover rate for the cinammon and pallid genes?

Jim

[kyria]

sigh! .. Just love it when he talks like that !

[Jay]

Where did you come up with the 3% crossover rate for the cinammon and pallid genes?

Crossover rates (AKA Recombinant Frequency or simply RF) are extrapolated percentages derived from breeding results (usually of Budgerigars) of double split males.

So for example, out of 10000 offsprings produced from a Normal/Cinnamon/Pallid male mated to a Normal hen:

75 were visual Cinnamon-Pallids hens
75 were Normal/Cinnamon Pallid cocks
150 were Normal cocks and hens

A total of 300 crossover offsprings out of 10000 translates to 3%. Hence 3% was the calculated value for the RF of these two loci.


Since an RF is an empirical data, it is not accurate. However, it gives a relatively clear representation of the distances between chromosomal loci among related species.

Among psittacine color morphs, the current RF are as follows:

Ino (Pallid) and Cinnamon 3%
Ino and Opaline 30%
Cinnamon and Opaline 33%
Blue and Dark Factor 14%


Hope that helps.

[Jim]

I see.

Thanks again for sharing your knowledge.

Jim

P.S. - I have a male moustache parakeet who wants to know how to get one of those 10,000 offspring testmating jobs.

[Jim]

One more thing you might help me clarify - The lower the RF the closer the two loci are on the chromosome, correct? The genes swap chromosomes during recombination in randomly cut strings and it seems to me that if one chromosome has the mutated pallid gene and the wild type cinammon gene it's very likely that both those genes will be in the same "swapped string" if they're loci are fairly close together and both mutated genes or both wild type genes will end up on the same chromosome only if the string gets cut in what must be a fairly small space between them. Is that how it works?

I hope any imprecise terminology doesn't offend anyone. This is what happens when a Certified Public Accountant takes an interest in molecular genetics...

Jim

[Jay]

P.S. - I have a male moustache parakeet who wants to know how to get one of those 10,000 offspring testmating jobs.

I would love a job like that too as long as no payment of child support is stipulated!

[Jay]

One more thing you might help me clarify - The lower the RF the closer the two loci are on the chromosome, correct?

Absolutely. The closer two loci are, the less likely they will be separated during meosis. Also, since RF is measured based on gene assortment, an RF of 50% is the highest possible value between any two loci. Anything more than 50% would indicate that the two loci are assorting as if they were located on two separate autosomal or sex-linked chromosome.

Some genetics books actually use RF's as a means of loci distance measurement and term this as Map Units (MU). So in essence, the Cinnamon and Ino loci are 3MU apart, the Cinnamon and Opaline loci are 33MU apart, etc.

The genes swap chromosomes during recombination in randomly cut strings and it seems to me that if one chromosome has the mutated pallid gene and the wild type cinammon gene it's very likely that both those genes will be in the same "swapped string" if they're loci are fairly close together and both mutated genes or both wild type genes will end up on the same chromosome only if the string gets cut in what must be a fairly small space between them. Is that how it works?

Partial strings of chromosomal genes (chromatids) are indeed swapped during meosis to ensure that each offspring gets genetic data from both sets of grandparents. The chromatids are cut along random points called chiasmata but each swapped chromatid has to be of the same length hence they are called sister chromatids.

You are correct in your example. Since the mutated Pallid gene and the wildtype Cinnamon allele from one chromosome are only 3MU apart, there is only a 3% chance of them separating. But if they do separate, the mutated Cinnamon allele from the other chromosome has to recombine with the mutated Pallid gene (on the same zygote) since chromatids can only recombine on equivalent chiasma points in relation to the other chromatids.

Also, as I stated earlier, a "side product" of this process is a zygote containing only wildtype Cinnamon and Pallid alleles.

I hope any imprecise terminology doesn't offend anyone. This is what happens when a Certified Public Accountant takes an interest in molecular genetics...

Worry not. No one is offended here as this will be taken as another learning opportunity. I'm an engineer myself who is also fascinated and intrigued with avian genetics.

[Jay]

sigh! .. Just love it when he talks like that !

[kyria]

P.S. - I have a male moustache parakeet who wants to know how to get one of those 10,000 offspring testmating jobs.

I would love a job like that too as long as no payment of child support is stipulated!

oooo you little stud you !

[Lauren]

P.S. - I have a male moustache parakeet who wants to know how to get one of those 10,000 offspring testmating jobs.

I would love a job like that too as long as no payment of child support is stipulated!

That made me giggle!