gen calc question
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gen calc question
Hi, I'm trying to get my head around the genetics of ringnecks, & can't figure out what the t1 & t2 split means when you check the (sf) dark & the split blue, it has the option T1 or T2 ? does anyone know what it means?
Re: gen calc question
Kimi, that is a difficult (and good!) question. Now, a dark factor / blue bird has inherited one dark factor and one blue factor from its parents. The question now becomes, which mutation was inherited from which parent? You'll see that it becomes necessary to know the parents of your breeding stock as well. Two scenarios exist to breed a dark factor / blue bird. I'll start both with an example, followed by a brief explanation of my somewhat limited understanding of genetics.
First case: An example is a D blue x green pair to produce a D green / blue youngster. Both mutations was inherited from a single parent at the same time, and only the wildtype genes from the other. This means that the mutated youngster will pass on both mutations at the same time to his/her young, or none at all.
Second case: An example is a parent pair of D green x blue, to yet again produce a D green / blue chick. One mutant allele was inherited from one parent (say dark factor from the father), and the other was inherited from the other parent (say the blue mutant gene from the mother). This chick will only be able to pass on one of these mutant genes at a time to a specific descendant, another descendant may inherit the other mutation, but never both at the same time.
However, you'll notice from Gencalc that, when using T1/T2, the probabilities aren't the same as what I have explained above. Sometimes there is a swap between sections of the father/mother DNA in the fertilization process. In this case, with the mutated alleles fairly close to one another, there is a 7% chance that the dark factor gene can be swapped for the wildtype gene. So in case one (above), we would expect the youngster to pass on both mutations at the same time, or none at all if no swapping occurred. If the swap does occur (and it does with 7% probability), then you'll only get 43% chicks with both mutations as originally expected. This is the outcome when pairing the youngster with a wildtype, or D green / blue (T2) x green. In the second case explained above, the youngster paired with a wildtype, or a pairing of D green / blue (T1) x green, you'd expect 50% D green and 50% green / blue chicks, i.e. only one mutation per chick. Now, with a 7% chance of the dark gene swapping with the wildtype gene, you'll end up with additional chicks, i.e. 7% now have both mutations, and 7% have no mutations at all.
Hope 1) I understand this correctly, and 2) that the explanation is clear enough. This is the most difficult question a breeder should be able to answer. However, you will almost never see the type included when purchasing a bird. Clearly from above, it is always a good idea to inquire about the parents of the bird you are purchasing, and to keep records of that as well.
PS: I am in now way a geneticist, and only interested in the topic. The above is merely my interpretation of what I have learnt so far, and may not necessarily be 100%. There are people like Madas and Recio on this board with a much deeper understanding of the topic, who may point out errors (if made, esp. with terminology) as the discussion progresses.
First case: An example is a D blue x green pair to produce a D green / blue youngster. Both mutations was inherited from a single parent at the same time, and only the wildtype genes from the other. This means that the mutated youngster will pass on both mutations at the same time to his/her young, or none at all.
Second case: An example is a parent pair of D green x blue, to yet again produce a D green / blue chick. One mutant allele was inherited from one parent (say dark factor from the father), and the other was inherited from the other parent (say the blue mutant gene from the mother). This chick will only be able to pass on one of these mutant genes at a time to a specific descendant, another descendant may inherit the other mutation, but never both at the same time.
However, you'll notice from Gencalc that, when using T1/T2, the probabilities aren't the same as what I have explained above. Sometimes there is a swap between sections of the father/mother DNA in the fertilization process. In this case, with the mutated alleles fairly close to one another, there is a 7% chance that the dark factor gene can be swapped for the wildtype gene. So in case one (above), we would expect the youngster to pass on both mutations at the same time, or none at all if no swapping occurred. If the swap does occur (and it does with 7% probability), then you'll only get 43% chicks with both mutations as originally expected. This is the outcome when pairing the youngster with a wildtype, or D green / blue (T2) x green. In the second case explained above, the youngster paired with a wildtype, or a pairing of D green / blue (T1) x green, you'd expect 50% D green and 50% green / blue chicks, i.e. only one mutation per chick. Now, with a 7% chance of the dark gene swapping with the wildtype gene, you'll end up with additional chicks, i.e. 7% now have both mutations, and 7% have no mutations at all.
Hope 1) I understand this correctly, and 2) that the explanation is clear enough. This is the most difficult question a breeder should be able to answer. However, you will almost never see the type included when purchasing a bird. Clearly from above, it is always a good idea to inquire about the parents of the bird you are purchasing, and to keep records of that as well.
PS: I am in now way a geneticist, and only interested in the topic. The above is merely my interpretation of what I have learnt so far, and may not necessarily be 100%. There are people like Madas and Recio on this board with a much deeper understanding of the topic, who may point out errors (if made, esp. with terminology) as the discussion progresses.
Last edited by Johan S on Thu Apr 19, 2012 11:00 pm, edited 1 time in total.
Re: gen calc question
thanx, maybe If I read it another 10-20 times I'll understand lol.
I was also curious about the general genetics of other parrots besides ringnecks, is it always the same rule? like can all wild type be split for blue? & are all lutino's sex-linked & just that mutations appear to look different in different species but have similar rules? like the whwt is just another form of a sex-linked mutationthat only occurs in ringnecks?, or are there specific mutations that act differently depending on the species?
hope that made sense .
I was also curious about the general genetics of other parrots besides ringnecks, is it always the same rule? like can all wild type be split for blue? & are all lutino's sex-linked & just that mutations appear to look different in different species but have similar rules? like the whwt is just another form of a sex-linked mutationthat only occurs in ringnecks?, or are there specific mutations that act differently depending on the species?
hope that made sense .
Re: gen calc question
I think I understand the question.
And yes, although some breeders sometimes comes up with a name for a mutation when they breed a specific species, the better approach is to define a mutation in such a way that it applies across all types of parrots/parakeets/birds (i.e. budgies, australian parakeets, ringnecks, african parrots, amazons and all the rest). And this definition is based on what is seen in all these species and includes inheritance mode, effect on melanin/psittacins distribution, change in eye colour (ino, pallid, fallow, etc.), beak/nail colour, etc. Thus, the pied mutation describes a mutation across all species, so does parblue, etc. As far as I'm aware, the cleartail mutation is only know for IRNs, but is already named correctly. The old name of WHWT/YHYT would not necessary apply to all species. As an example to illustrate this, the blue mutation is a bird with a complete psittacin reduction. Therefor, only melanin will be visible (if there is melanin present) and a green bird will become blue. (If you mix blue and yellow paint/ink, you end up with green. So if you have green and remove the yellow, you end up with blue). However, a blue african grey will be a grey bird with a white tail (the red of the original tail is from psittacin, which gets removed) and no blue feathers anywhere (google search for blue or white tailed african greys for some pictures). Which is why it is confusing when using a colour to name a mutation (I think it should be avoided), as it doesn't seem to apply very well to all parrots/parakeets, yet they have the same mutation that causes the same effect at a genetic level, rather than at a visible (phenotypical) level.
And yes, although some breeders sometimes comes up with a name for a mutation when they breed a specific species, the better approach is to define a mutation in such a way that it applies across all types of parrots/parakeets/birds (i.e. budgies, australian parakeets, ringnecks, african parrots, amazons and all the rest). And this definition is based on what is seen in all these species and includes inheritance mode, effect on melanin/psittacins distribution, change in eye colour (ino, pallid, fallow, etc.), beak/nail colour, etc. Thus, the pied mutation describes a mutation across all species, so does parblue, etc. As far as I'm aware, the cleartail mutation is only know for IRNs, but is already named correctly. The old name of WHWT/YHYT would not necessary apply to all species. As an example to illustrate this, the blue mutation is a bird with a complete psittacin reduction. Therefor, only melanin will be visible (if there is melanin present) and a green bird will become blue. (If you mix blue and yellow paint/ink, you end up with green. So if you have green and remove the yellow, you end up with blue). However, a blue african grey will be a grey bird with a white tail (the red of the original tail is from psittacin, which gets removed) and no blue feathers anywhere (google search for blue or white tailed african greys for some pictures). Which is why it is confusing when using a colour to name a mutation (I think it should be avoided), as it doesn't seem to apply very well to all parrots/parakeets, yet they have the same mutation that causes the same effect at a genetic level, rather than at a visible (phenotypical) level.
Re: gen calc question
Mutation naming is quite a detailed and collaborated process. Since it requires agreement and consensus you will find variations in naming precisely because of that challenge. Not everyone is in agreement and some are openly against certain names.
Wild color green birds normally manifest blue mutations. Lutino appears in sex linked and recessive genes.eg the sex linked and non sex linked lutino in the Indian ringneck.
I am aware of the so called blue mutation in the African grey parrot. Its the white tail in this mutation that gives rise to this name, yet the bird isn't blue in color. I think that this will probably be renamed appropriately...then again maybe not.
The point is , mutations in birds is a vast subject and requires study and research for any keeper to hold some level of understanding here. I recommend Terry Martins book on the subject.
Wild color green birds normally manifest blue mutations. Lutino appears in sex linked and recessive genes.eg the sex linked and non sex linked lutino in the Indian ringneck.
I am aware of the so called blue mutation in the African grey parrot. Its the white tail in this mutation that gives rise to this name, yet the bird isn't blue in color. I think that this will probably be renamed appropriately...then again maybe not.
The point is , mutations in birds is a vast subject and requires study and research for any keeper to hold some level of understanding here. I recommend Terry Martins book on the subject.