electric blue jack demsey is a hybrid?????

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koliveira;859350; said:
did you guys red the article? Or see the source? ACA also believes them to be hybrid. Iused to believe they were line breed as well. I now know otherwise.

Kory

i do not think that that line breeding would create this effect of breeding the "line bred fish" with the original/"plain fish" would not create fish carrying a gene to then carry on to make the original while still creating other fish that still carry the gene making them blue!

this is a sign of genes not line breeding or hyrbidization! as the link i gave before said that no one had been able to get the same effect with their own hybrids!

if some one disagrees i will include a little more to help explain it too!
 
I think it's about time I got involved in this thread. I'm with rmcder on this one for the following reasons:

1) The genetic results are too clean for inheritance not to be Mendelian.
2) The same results occur every time blues are produced.
3) The fry all look the same.
4) Not enough people are trying to breed pairs of blues to prove they can't produce viable young (and if you read the article apparently Luzardo had breeding pairs of blues).
5) Jeff Rapps had the DNA test done (although I'd still really like a copy!). Seeing as my PhD is on speciation in lizards, I can tell you that you'd almost certainly find genome differences between JDs and Jaguar cichlids (possibly the only thing my PhD has been good for!).
5) I just spent all day translating the useful bits of the Spanish article on the elacuarista site and while the company seems to admit that they are hybrids, there are tons of loop-holes in the story that mean that Hector Luzardo himself probably had no idea where the hell blue dempseys came from!

Here's my translation. If anyone has better Spanish than me then please go ahead and correct this. I think you'll find that the general meaning comes out the same:

----------------------

Reproduction: The reproduction of the Blue Dempsey is obtained in the same way as the Jack Dempsey. Any fan can try it if they find a pair.


Having said this, we have encountered a number of difficulties that must be overcome in order to breed the Blue Dempsey, as it appears that the same genetic process that produces the mutation inhibits fertility [between two blue parents – Ed.].

During years of experience reproducing the blue variety of Nandopsis octofasciatus very few offspring have come from using blue dempsey parents (i.e. two blues). That does not mean it has never happened. It has occurred, but with very many difficulties and a lot of care taken of the fry, especially during the first few days after spawning. The failure is always associated with small variations in temperature and/or deficient feeding (we thought that it must be some form of digestive enzyme deficiency in the early stages of feeding).

For those who are not experienced in the reproduction of cichlids, we will say that Blue Dempsey reproduces in a manner typical of most members of the Cichlasoma genus (and, for that matter, most other cichlids). The pair dedicates a lot of effort into establishing a territory, which they maintain and keep free from intruders. Within the chosen area they meticulously clean an egg-laying site, which they also defend from intruders. Generally they choose a large, smooth stone resting at an upward angle. The female deposits eggs in fairly regular rows, which are fertilized by the male once each row is complete. After 72 hours the fry hatch and are jealously guarded and watched over by both parents, who carefully collect and replace any fry that wander out of safety. Fter a few days they are transferred to another site in the aquarium, previously cleaned by both parents, until the fry begin free swimming. It is at this moment when the parents begin to be hopeless at looking after the fry, who are already trying to move around, swimming clumsily. Up to that point the fry do not display much more than a grey coloration, almost identical to similar sized fry of any other cichlid. After 45-50 days the characteristic sky-blue coloration begins to appear and this intensifies over the course of time. From now on the maintenance and feeding of the young, just like the later development, is similar to that of any member of the Cichlasoma, Heros or Nandopsis genera. It should be emphasized that in pairs of Blue Dempsey the extreme aggressiveness of the male (observed in the common pairs of Jack Dempsey) does not exist. That is to say that the female is not so severely punished nor hurt during the breeding process. Therefore is not necessary to remove the male from the aquarium once the eggs have been fertilized.

History: The individuals (that carry the blue gene) that were used in the creation of the Blue Dempsey were no different in appearance to common Jack Dempseys. But, to be honest with other aquarists or professionals who attempt their reproduction, it is necessary to say that before obtaining the Blue Dempsey, there were spontaneous crosses between Nandopsis octofasciatus and other varieties of Central American cichlid, such as Cichlasoma managuense and Cichlasoma synspilum that produced infertile young if crossed with one another. See note on the matter [Link to the info below, which has been translated and shortened to the bare essentials – Ed.]

Some years ago a friend [gave Hector Luzardo a pair] of Cichlasoma synspilum, from Guatemala…Another friend [gave a him some pairs of] Cichlasoma managuense from El Salvador, Costa Rica and Honduras. [Mr Luzardo was already keeping Jack Dempseys]. Of the [hybrids produced by crossing these fish] some young died, others never hatched and in some cases offspring similar to one or other of the parents survived. Over the course of time only Jack Dempseys (N. octofasciatus) remained in the hatchery, which produced descendants that did not offer differ to other members of the species [which is not to say that these fish were hybrids! - Ed.]. Of those fish, hundreds were sold until the market was flooded. Luzardo gave the remaining fish away since they occupied space required for raising other fish. Time passed and then in 1985, the friend to whom [Luzardo] had given those remaining young Jack Dempseys gave a pair back to him [not necessarily the same fish Luzardo gave away - Ed.] that had laid eggs in their community aquarium but had never obtained young as the eggs were devoured by the other inhabitants of the aquarium. It is here where really the true history of the Blue Pacíficum begins (this is the name that Luzardo gave the EBJD to identify the habits [pacificum = peaceful] of this hybrid variety)…Placed in a aquarium on their own the Jack Dempsey pair did not take long in laying eggs, producing around 2000 eggs per spawn…Around 20 days after being born, the young were moved to new aquariums. In one of the so many daily inspections that Luzardo makes in the hatchery, he observed that a small amount of Jack Dempsey young, were grouped in a corner of the aquarium, while the rest swam freely…They were transferred immediately to a separated aquarium [Luzardo thought they were dieased], where he could better monitor their progress…After some time, the separated units displayed a bluish coloration clearly which left no doubts over the fact that they represented a new mutation..This does not mean that it wasn’t there before, but considering that very young Jack Dempsey still have the aggression of cichlids, it is very probable that the small amount of "mutants" had been destroyed previously by their siblings.

[Now back to the main document]

Of the fish that resulted from these crosses, a number had all the characteristics of Nandopsis octofasciatus, some with indefinite characteristics and others with characteristics of Cichlasoma managuense. Finally those that did not have the characteristics of a Jack Dempsey were discarded. For this reason we suppose that the appearance of the blue gene must come from some of the units crossed with Cichlasoma managuense but that had the appearance of N. octofasciatum. [But it's very, very unlikely you'd get fry that all looked the same if these fish bred, especially over several generations. And how in hell would you get a blue gene from a Jaguar cichlid? - Ed.]

Here’s some more from the note section:

A single report [of a successful EBJD x EBJD spawn producing young] is not known anywhere in the world [outside of Luzardo's hatchery], although [Luzardo] sold many thousand of small Blue Dempseys. It should be noted that although the production of young from two blues has not reported, in the Luzardo’s hatchery there are pairs of Blue Dempseys (two blue parents) producing fry identical to their parents. Luzardo is currently raising blues for export to the United States, while it faces a new project to increase production with the purpose of also exporting blues to Europe.

------------------



This by no means settles the debate, but I wanted to make it clear that the Luzardo story is far from clear. In the absence of Mr. Luzardo, who has passed away, it would appear that no-one remains who could say what was breeding with what and whether it was in tanks or pools and where those last few JDs he gave away came from. The word hybrid is mentioned, but there's no real evidence to support the hybrid claim other than they're hybrids because those guys in Argentina say they are, and they're not really sure are they? After all they told Jeff Rapps they weren't hybrids...

The weakest point in the above story is that a small percentage of the fry were blue dempseys and the rest were normals. If the parents had been hybrids then there would have been a continuum of fish, some that looked like JDs, some that maybe looked like jags and some that looked in between. There's no way a small batch of young would stand out in a massively varied group of fry like that, whereas if the parents were BGJDs (Blue gene carriers) then only the blue fry would look abnormal as the rest would either be straight normal JDs or blue carriers like their parents:

B = normal colour gene

b = blue colour gene

Bb x Bb -> 25% BB, 50% Bb, 25% bb as follows:

B b
---------------
B BB Bb

b Bb bb

As for the ACA, well they do wonderful things for cichlids, but at the end of the day they're still people and people make mistakes. People are also quick to choose the path of least resistance (I speak from experience!). I'd like to hear the reason the ACA don't accept them as a true species.

Is it because of a website written in Spanish where they say it's a hybrid but don't really know what it's a hybrid of, and where the spokesperson for the 'creator' of these fish admits that at the time of writing they knew nothing about genetics, science or biology (Read it, it's there!)?

Is it because two blues don't produce extant fry (members of the EBJD forum have produced free-swimming fry from blues and Luzardo's company claims to have breeding pairs of blues)?

Or is it because no-one wanted to pay for the requisite DNA testing and so they thought they'd go with the low cost, low time option?

TBH I don't really care what the reason is. What I do believe is that you shouldn't believe anything until you've got enough evidence to sway you strongly one way or the other. To my mind the evidence supporting the hypothesis that EBJDs are not a hybrid far outweighs the conjecture and internet rumour-mongering that says they are.

That's why I believe EBJDs are a colour morph of Nandopsis octofasciatus, not a hybrid.

Thanks for your time,

Bluejax ;)
 
very interesting. it's just all strange how it works.

i am also lost to the statement that one guy created these. and how they just showed up, after how many decades of ppl keeping JD's.

the thing i have a problem with is. i've been keeping JD's for many years. and many of the "adult blues" i've seen, look strangely different in form then a true JD. example: blues tend to have a longer head and snout and body then a true JD. how are these differences noticeable if the fish is exactly the same as a JD?

well great info on everyones part. :popcorn:
 
fishfreak317;861205; said:
the thing i have a problem with is. i've been keeping JD's for many years. and many of the "adult blues" i've seen, look strangely different in form then a true JD. example: blues tend to have a longer head and snout and body then a true JD. how are these differences noticeable if the fish is exactly the same as a JD?
Do all jds look exactly the same, or just approximately the same? The problem with genetics is that often times traits are linked, so a blue color may be linked with different finnage or with overall size. It isn't always a single change that occurs. Also, the line of blue dempseys has been selectively bred to enhance its differences, so there could have been some drift in the body shape, much as various breeds of dog look considerable different as a result of selective breeding, but are still dogs. I wonder what the very first ebjds looked like; maybe they DID look exactly like "normal" jds other than coloration.
 
rmcder;861689; said:
Do all jds look exactly the same, or just approximately the same? The problem with genetics is that often times traits are linked, so a blue color may be linked with different finnage or with overall size. It isn't always a single change that occurs. Also, the line of blue dempseys has been selectively bred to enhance its differences, so there could have been some drift in the body shape, much as various breeds of dog look considerable different as a result of selective breeding, but are still dogs. I wonder what the very first ebjds looked like; maybe they DID look exactly like "normal" jds other than coloration.

yea this is totally different than dogs! it would be very hard to get in the right colors! having to use BGJD and the original!
 
I wouldn't rule out selective breeding as an explanation for blue dempseys having an unusual facial profile. It's certainly not the facial profile of a jaguar cichlid or a synspilum...

On a more important note, I thought I should let you guys know that the DNA test Jeff Rapps had done only proves that a female jack dempsey was used in the creation of the EBJD. The test compared mtDNA (mitochondrial DNA) between EBJD, normal JD and C. citrinellus. The results show that the DNA sequences are identical between EBJDs and normal jacks, but not C. citrinellus.

Mitochondrial DNA is inherited from the female parent only, as sperm do not contain mitochondria. Hence, although we can say that EBJDs are 100% related to the maternal lineage of N. octofasciatus, we cannot say anything about the paternal lineage.

A test on nucleic DNA would be required to fully rule out the possibility of these fish being a hybrid.

It is important to remember that this test in no way implies that EBJDs are a hybrid. The evidence from the patterns of genetic inheritance and the uniformity of EBJD spawns would suggest otherwise.
 
Bluejax;864696; said:
I wouldn't rule out selective breeding as an explanation for blue dempseys having an unusual facial profile. It's certainly not the facial profile of a jaguar cichlid or a synspilum...

On a more important note, I thought I should let you guys know that the DNA test Jeff Rapps had done only proves that a female jack dempsey was used in the creation of the EBJD. The test compared mtDNA (mitochondrial DNA) between EBJD, normal JD and C. citrinellus. The results show that the DNA sequences are identical between EBJDs and normal jacks, but not C. citrinellus.

Mitochondrial DNA is inherited from the female parent only, as sperm do not contain mitochondria. Hence, although we can say that EBJDs are 100% related to the maternal lineage of N. octofasciatus, we cannot say anything about the paternal lineage.

A test on nucleic DNA would be required to fully rule out the possibility of these fish being a hybrid.

It is important to remember that this test in no way implies that EBJDs are a hybrid. The evidence from the patterns of genetic inheritance and the uniformity of EBJD spawns would suggest otherwise.

Very interesting!!
Well, maybe someday we will have 100% conclusive evidence. Thanks for sharing!

Kory
 
Bluejax;864696; said:
I wouldn't rule out selective breeding as an explanation for blue dempseys having an unusual facial profile. It's certainly not the facial profile of a jaguar cichlid or a synspilum...

On a more important note, I thought I should let you guys know that the DNA test Jeff Rapps had done only proves that a female jack dempsey was used in the creation of the EBJD. The test compared mtDNA (mitochondrial DNA) between EBJD, normal JD and C. citrinellus. The results show that the DNA sequences are identical between EBJDs and normal jacks, but not C. citrinellus.

Mitochondrial DNA is inherited from the female parent only, as sperm do not contain mitochondria. Hence, although we can say that EBJDs are 100% related to the maternal lineage of N. octofasciatus, we cannot say anything about the paternal lineage.

A test on nucleic DNA would be required to fully rule out the possibility of these fish being a hybrid.

It is important to remember that this test in no way implies that EBJDs are a hybrid. The evidence from the patterns of genetic inheritance and the uniformity of EBJD spawns would suggest otherwise.

hmm it said to be very hard to breed a female EBJD with a male of an BGJD or a JD!:WHOA:
 
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