A question of genetics

Hi Prof. Dirk

I hope you are well. I have a question which relates to genetics. Its something I have been giving some thought, but obviously with limited knowledge of genetics I am most probably heading down "assumption street".
My question is related to the breeding of Heckel discus. Its been widely reported that getting the female Heckel to spawn is where the problem lies. Male heckels will quite easily spawn with other, willing females, but getting the female heckel to spawn is deemed extremely difficult.
This coupled with reports of reducing quantities in the wild, and the destruction of the Amazon rainforest, puts the Heckel, and for that matter all discus at risk. Now the Singapore university did research on the DNA structure of Discus some time back (you and I discussed this before) and found the Heckel to be twice as genetically diverse as any of the Aquif. strains. My understanding of this is that the Heckel comes from a more diverse pool, and also has more genetic potential than any of its counterparts. Please correct me when I'm on assumption street.
My question to you is the following, and it relates to bridging the divide between establishing a good tank bred line of Heckels.
Hypothetically speaking- if I was to cross a Heckel male with, lets say a brown female.
The f1's will now be Heterozygoes Heckel, having one Heckel gene, am I right?
Its been reported that all Heckel characteristics goes missing once that F1 is line bred, ie. the Heckel bar in f2 is already missing.
BUT. . . What if I now breed a female F1 back to another Heckel male, again arriving at what we can call a new F1. I then keep doing this for every generation, always breeding a female from the "cross" back to a Wild Heckel male.
The conclusion of my long hypothesis-
Do I at some stage arrive at a Homozygoes Heckel again, which if F1 is line bred will breed true to Heckel character.

Sorry for the hypothetical question, its just something I have been thinking of, hehehe.

Thank you

Regards

Marco

 

Hi Marco,

This question actually requires me to write about a book to answer it! But let me try to reply in less than a book.

Firstly, in all wildcaught discus, and altum angels for that matter as well, it is the females that are difficult to get to spawn, not only in Heckels.

Then, I think that the assumption about the greater genetic diversity in Heckel discus, is not correct in the light of more recent information. There has been a recent publication in which the genetic relationships and diversity between many of the discus from the different rivers in which they occur were compared and the results of this study are quite difficult to interpret and very difficult for the lay person to understand. From this study, it is apparent that Heckels from the Rio Negro are quite distinct from other discus but that the Heckels from the Rio Nhamunda are actually already not pure but are hybrids between original Heckels and blues. Also this study does not support the greater genetic diversity idea that the Singopore scientists found, in my opinion because the sampling of the Singapore scientists was only from domestic discus and not from the wild. So the assumption that the Heckel has more diversity is not supported and not valid.

In principle, the repeated backcrossing of male Heckel onto a domestic female or subsequent cross is correct, you should eventually get something that would be identical to Heckel, that is correct, but there is not only one "Heckel gene" as you call it, Heckel's colour is definitely controlled by more than one gene which is also what make the breeding to maintain the "Heckel bar" so difficult. Furthermore, you must remember that if you now have a female that is say 3/4 Heckel, will she spawn? You would be getting back to the problem of female Heckel's not wanting to spawn, can you see. You could maintain the Heckel bar after making a cross with a S aquafasciata discus, but using the F1 males and females for breeding but then selecting offspring for the Heckel bar, but still keeping the easier breeding.

My personal opinion is that one can get Heckel's to spawn but that one needs much more careful detail to water conditions. This is almost the same with altum angels. Even if they are captive bred, which definitely makes the females easier to get to spawn, you still have to have the water and aquarium conditions perfect if you want them to breed.

There is a guy in Poland who has been breeding Heckel's recently as well as many hybrid discus, but I think his website is down now, so one cannot get to his website. However, I think his fishes are Nhamunda Heckels and not Rio Negros. Try to find Superdiscus, I also think there are some utube videos. He has managed to get them to breed because he has the conditions just right, and this is what one needs to achieve.

Kind regards,

Dirk

 

Hi Prof Dirk.

Thank you for taking the time to explain and answer my question.

I am aware of the Polish gentleman, I think his name is Andreij Nowieckjie, who had two succesfull spawns with his Heckels. To my knowledge, you are also right that he did not manage to spawn the supposedly even "more" difficult Rio Negro type.
I have read his story and he is fortunate that he gets almost perfect water from tap in Poland, something like water with a ph of 4 and a tds of only 20. Absolute perfect I would think.

The other problem with my question is off course one of time. . . It would take you close to ten years to get anywhere close to a reliable line of Heckel in this way I suppose.

I know many people have been trying to get them to spawn. Most people who seem to have had success lost the fry, and then could not repeat the exercise. Its absolutely amazing that in this day and age some things still remain a mystery to us. I chatted to Dale Jordan some time back, via email. He managed to spawn both type of Heckel in the 90's, and his honest opinion was, sheer luck!

I sure do hope we manage to get an established tank bred line of Heckels sooner rather than later.

Rgds

Marco

 

Hi

Now here is a sight you dint get to see everyday. . .




This is the second successful spawning of the Wild Heckel in recent times. These are Rio Negro Heckels, confirmed as such by Heiko Bleher. The breeder who lives in Budapest gave the following water parameters as the key to breeding them. At the moment he has about 80 fry!

Ph 4.0
99%RO water
Temp 29
Tds 40-60 (made up of normal bio activity, tds of RO water added 8ppm)

Congrats to him on this amazing feat. Many of you maybe dont realise just how rare and difficult it is to spawn the Heckel. This is only the 2nd batch of fry seen in the past 10 to 15 years!

Really amazing news!

 

I watched the video's of that poland guy that has also bred them, I also saw the photo's on his facebook page. This must be one amazing feeling that one person can have. Ph of 4? I can only dream about that without having to manipulate the water that much.

You'll get there with your greens and then this will be your next challenge, have faith!!!

 

@Laracroft

Pffft, I snt know hey. Needs some serious water management to attempt breeding Heckels. Might just be beyound my scope and expertise. They sure are nice though!