Alexandrine Mutations

[Recio]

Hi Saud;

Congratulations for your web page!!!

Do you know which is the rate fertility of first generation hybrids (males and females) from a male lutino IRN X wild female alex ? I understand that the fertility rate must be lower in female hybrids since they only carry one sex cromosome coming from the lutino male IRN and there is not anyother to counter balance possible "deletereous" effects .... but what about first generation hybrid males?

Greetings

Recio

[Recio]

Hi;

I hope you will get your lutino, blue and albino alex.
Keep us informed and take pics of the outcomes at different Gs

Recio

[julie]

looking at my big boof head alex at the moment (kinda hard not to he is barking like a dog) and he is housed with a male indian.
Cant help but ask with the size difference wouldnt it be easier for a female Alex and male indian?

[xx_sheena_xx]

if they used a female alex and a male IRN the male wouldnt be able to mount the female properly

[Recio]

Hi Saud;

Today is father's day in France and my wife has offered me Bastiaan's book "Asiatic parrots and their mutations" .... more than 500 pages of pleasure to study in the days to come. In the introduction chapter he says that crossbreeding alex and IRN to transfer mutations will never allow to get a "pure" mutated alex since the size remains always small when compared to wild alex, even after 5 generations of back-breeding as you have described.

In fact at each time that you cross the hybrid bird back to a pure alex you think that you are diluting at 50% the IRN genetic pool, and that doing it many times will allow you to almost make disapear the IRN genes excepting the one you are selecting: the lutino gene.

This is not really true because genetic information is packed in cromosomes, which can not be "cut" indefinitely. To transfer the lutino gene from IRN to alex will depend more on the chance of getting the right crossingover allowing the lutino gene to move to the X cromosome of the alex, than on trying to "dilute" again and again by backbreeding to pure alex. As you know crossing over depends on the presence of specialized areas in the cromossome (called "chiasmas" in french, I do not know in english) ... so I wonder if alex and IRN sexual cromossomes are "compatible" to exchange genetic information.

In a post some months ago I hypothesized about the possibility of a major gene related to size being located in the sexual cromosomes:
http://www.indianringneck.com/forum/vie ... namon+size

The fact that "lutino alex" remain of small size after G5 or more add more consistency to the hypothesis of a major gene concerning size located in the X cromossome (like lutino and cinnamon genes). The lutino gene would be coupled to the IRN size determinig gene ... and so every lutino alex will also display a lower size .... till the time crossing over allows them to separate.

The question is: can sexual cromossomes of IRN and alex cross over?

Let me know what you thinck ... you are our geneticist !!!

Regards

Recio

[Recio]

This looks like a great book and I have added it to my wish list Can you tell me the price of the book?

Hi Saud;

The book is a gift of my wife and she does not want to tell me the price, so I guess it is not cheap. You can directly contact Bastiaan for the price (his mail: jac.bastiaan@wxs.nl).

It is my understanding that the concept of crossover becomes important only when dealing with genes on the X chromosome or in other words with sex-linked mutations.

Crossing over occurs in every paired chromosomes and it allows to "mix" genetic information from parents. Genes located in different chromosomes are independent in their transmision but those which are located in the same chromosome are linked and the % of offspring you obtain for each mutation depends actually of the distance between the loci of each mutation and the crossing over rate.
Crossing over is important in sex linked mutations (opaline, cinnamon, lutino/pallid) and also in other mutations located in autosomic chromosomes as blue/turquoise/aqua and dark. Have a look to the genetic calculator: what do you obtain when pairing a darkgreen male split blue to a green split blue female? As you can see the dark gene and the blue gene in the male can be together in the same chromosome (crossingover type 1) or can be located in separate chromosomes (crossingover type 2). Test each possibility and try to explain the results.

In the previous thread, you have mentioned that size is polygenic. Even If we were to accept that an important gene for size resides on the X chromosome, it would still be possible, in theory, for other size genes to offset the effect of this gene over a sufficient number of generations. Even if some of the other size genes are recessive we could still improve size by selective breeding and pairing back to larger normals.

I agree totally

In my internet research I have seen claims that the 5th generation birds are virtually indistinguishable from the normals. It is also reported that with each generation the birds improve.

I have not experience in this subject but Bastiaan claims that even after G5 the hybrids remain of smaller size. He also says that hybrids do not display a solid red wing patch but a broken orange patch and they have a rounded head shape instead of the flat head of the genuine alex... so try to choose a female IRN with a flat head to begin.

It is also my understanding that a relatively small number of genes define the distinguishing traits in a species. For instance humans and chimpanzees have 98% genes in common. With Alexs and IRNs being much more closely related I would expect this to be much higher. Furthermore, the two species seem genetically compatible as the hybrids breed back sucessfully to normals over several generations. On the basis of this I would expect genetic crossover to occur.

Yes, I think so. Probably genetic similarity between IRN and alex reaches more than 99.9% (humans and anelids share 50%), but this little <0.1% makes all the difference.

I cannot find a picture of a 4th or 5th generation hybrid male right now but I am sure I have seen some. I also recall that the neck ring in these birds looked very much like an Alexandrine and not like an IRN. I would expect the major genes controlling the neck ring to reside on the X chromosome. Given that both X chromosomes in the male originate from the IRN this is a surprising result. Does this mean there is crossover?

Maybe but not necessarily: having a ring or not could be regulated by genes located in the X chromosomes, but the way this ring is expressed (wide, intensity, ...) could be regulated by other genes.

I have seen on his website that Bastiaan is also keeping Lutino Alexandrines. Does he mention in his book how he acquired the mutation?

No, he does not ... and I guess you are smiling

Regards

Recio

[Recio]

A friend and very good breeder told me: "Sell your valuable birds with parsimony to avoid overflowing the market and to wake up the interest of other breeders". It could explain why they are always expensive. This breeder bought a pair of lutino alex last year for 5000 euros (6000 dollars) but it was to late to make them breed this year.

Regards

Recio

[julie]

Out of curiosity
Why do 'pure' Lutino Alexandrines still cost a fortune years after they were first reported?

I would say because people who dont want to go through the whole process of getting a "pure" coloured alex would be buying them.

[Recio]

Hi;

Yes I can see the flat heads, but the beak seems smaller than in the genuyne alex and the whole size is difficult to appreciate. Lutinos display an orange patch (instead of red) and in one of them the patch is broken. Lutinos and blue have not developped the ring so we can not appreciate the final "look". Anyway they are beautyfull birds.

Recio

[iqbalniazi]

Hey...

I am new to Indian Ringnecks and Alexandrines but I have been breeding a wide variety of doves. (only three types but that is wide for me xD). I have known someone that is trying to do what you want in doves (i know they are not parrots). But I thought that you would like to see what he has done. Below are the articles.

http://cl.ly/1lI3 (Senegal Dove)
http://cl.ly/1lbY (Laceneck Dove)
and there is a lot more that he has done with the Streptopelia Species.

Good Luck.