Xanthism

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Bluejax
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Xanthism

Post by Bluejax » Tue Sep 09, 2008 12:36 pm

I currently have hundreds of 0.5" babies from a pair of jags whose father is the world's only xanthic managuense (pic below). As such the parent fish are carriers for the xanthic gene (if indeed it is a single gene).

Image
Xanthic jag (only one in the known universe!)

I've asked on other forums, but I was wondering if I could get any more info on the inheritance and expression of xanthism here.

My collaborator and I are working on the assumption that the xanthic gene is recessive and hence 25% of my current spawn should be xanthic, with 50% being carriers and the remaining 25% being 'normal' jags.

I have a few questions:

1) Is xanthism generally a recessive Mendelian gene? Do we know from other species? I am wondering if in this case it might be codominant or something as the female parent is very yellow for a jag (top fish in pic below, which doesn't do them justice):

Image

2) At what size do xanthic fish become xanthic? I have read about three or four species where the xanthic colouration only appears well into maturity - one example being the xanthic female nicaraguense in one thread on this forum. Anyone got experience with xanthic fish that they've grown from a very young age?

3) How quickly do xanthic fish become xanthic? I heard stories of it happening in a matter of a few days.

We are worried that the young we have won't even begin to look xanthic until around 4-5" in size. Given we have several hundred of these fish and no idea which are xanthic all we can really do is sell them and hope to keep enough so that we eventually end up with a few pairs that are xanthic, as no-one has space for several hundred 5" jags!

I hope you can see why we need some help with this. Any and all (constructive) comments welcome. :D

Bas Pels
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Re: Xanthism

Post by Bas Pels » Tue Sep 09, 2008 2:34 pm

Although I much rather see the normal pics thna the others, and should I be as unfortunate as to face xantism, I will destroy all misfits, I will still try to help you

Fistly, normal * yellow will, assuming you are right ans yellow is recessive (I think so too) produce 100 % normal looking offspring.

The reason why I think yellow is recessive, is that I think yellow is a failing of the mormal genes - to produce the black pigment the normal fishes have. What I don't know is how much genes are involved, and how much are failing

Let's assume 1 gene is involved. Half of the offspring gets the defective genes from dad, and half the ofspring from mom. 1/2 * 1/2 = 1/4 th, thus the F2 should be yellow, the others normal

In case 2 genes are involved, the same will apply, and therefore 1 out of 16 will have both genes missing, 1 out of 4 one of them, and 1 out of 4 the other. In case both need to be missing to produce yellow offspring, only 1 out of 16 will be yellow. In case only one of the genes needs to be missing (vetoing the production ofthe black pigment) 1/4 + 1/4 - 1/16 (overlapping parts) = 7/16th yellow

By breeding with the yellow parent you might improve this even further (handy in case more genes are involved)

The yellow F2 might not breed purely in case more than 1 gene is involved

As I never had yellow fishes, I can not answer your other queries.

I do, hoever, foresee you will need a lot of room to produce more yellow fry

I would ask you for 1 favour: please do not sell normal looking fry which might have yellow genes: People might actually prefer normal fishes (as I do) and feel somewhat cheatred if fry appears to be yellow.

Bluejax
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Re: Xanthism

Post by Bluejax » Tue Sep 09, 2008 4:15 pm

Xanthic fish aren't hybrids, nor are they weaker than normally marked fish. Just a colour variant of a pure species. As such I will most likely be selling these fish.

My original aim was to keep the xanthic line pure, so that only full xanthics are sold and not xanthic carriers. That way gold jags and normally marked jags could easily be kept separate in the trade. Sadly I don't have the tank space for such an endeavour.

My current aim is to find out if the carrier pair I own are even producing xanthic fry or not. Seeing as I can't keep all the fry it makes sense to pass them on to people so that hopefully someone will be able to confirm that xanthics are being produced.

Anyone else got anything to contribute to this thread?

Mark Smith
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Re: Xanthism

Post by Mark Smith » Tue Sep 09, 2008 5:35 pm

I see nothing wrong with attempting to maintain and perhaps fix the xanthic mutation of this species. More power to you. We see xanthic mutations in the wild, and in my opinion, having them in captivity is fine.

Bas Pels
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Re: Xanthism

Post by Bas Pels » Wed Sep 10, 2008 1:34 am

whether you like it is, I think, a matter of taste - which is hard to discuss

I have my opinion, others have theirs. I see no problem

However, I wrote about normal fish whgich happen to carry yellow genes - thus getting something I did not expect. No more, no less

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illustrator
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Re: Xanthism

Post by illustrator » Wed Sep 10, 2008 4:23 am

Not al xanthic (or leucistic) variants inherit in the same way. The general rule is that these mutations are single-gene recessive and are expressed from the moment dark pigment is formed, that is, if you look carefully you can see it in very small fish, even in wrigglers it might be visible. Exeptions are midas cichlids and (orange)goldfish, which start out as normal fish and gradually turn yellow (orange) in later age.

If my assumptionis correct (single gene, recessive), you can expect the following:

xanthic x normal = 100 % carriers (= normal looking)

carrier x carrier = 25 % normal, 50 % carrier, 25 % xanthic

xanthic x carrier = 50 % xanthic, 50 % carrier

carrier x normal = 50 % carrier, 50 % normal (note that in this case you will have no clue which individuals are carrier and which are normal!)

xantic x xanthic = 100 % xanthic

So my strategy would be (in case I would want to breed xanthics): cross the xanthic with an as yellow as possible normal individual. Even better with a related normal individual (which might be carrier!). The offspring will most likely be all normal, but carries the recessive mutation. Keep a few of these (the most healthy, best shaped, good growing ones! – It doesn't make sense to raise hundreds, just enough to ensure that you raise both males and females. Maybe 20 will do.) Then either back-cross a doughter with the xanthic father (50% of offspring will be xanthic) or cross brother x sister (25% will be xanthic). Once you have more xanthic individuals you can continue with xanthic x xanthic, but take care that you always select only he best individuals for breeding as inbreeding (like this) might also bring out other mutations (like deformities). My experience wth leucistic (white) convicts is that survival of leucistic ones is not as high as survival of normal ones, probably because white fish stand out more and are more often eaten by other aquarium inhabitants.
Last edited by illustrator on Wed Sep 10, 2008 8:03 am, edited 1 time in total.

Bas Pels
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Re: Xanthism

Post by Bas Pels » Wed Sep 10, 2008 4:40 am

as Illustrator pointed out, you will, most likely, not need to raise much fishes to get, in the end xanthic ones

However, assuming the xantism is visible from birth, I would rather continue as long as possible with xantic father * carrier daughter: their offspring will - genetically - be better than their xantic offspring amongst each other - less inbreeding

The batches of fry are far too large anyway, so you can only raisepart of them - less then the half xantic ones
Last edited by Bas Pels on Wed Sep 10, 2008 8:59 am, edited 1 time in total.

Bluejax
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Re: Xanthism

Post by Bluejax » Wed Sep 10, 2008 6:36 am

xanthic x carrier is correct as 50% xanthic and 50% carrier:

If xanthic gene = y (recessive), and normal gene = Y (dominant)

xanthic fish = yy (two recessive genes)

carrier fish = Yy (one of each gene)

Therefore using a Punnet square:

Y y
------------------------------
y Yy yy

y Yy yy

Hence 50% are Yy (carrier) and 50% are yy (xanthic)

The fry seem to show no hint of xanthism up to 3" plus, but there are certainly several other species than midas and goldfish that show xanthism much later in life (i.e. not from the fry stage).

Illustrator, as you say the best percentage of xanthic fry would be from xanthic male and one of his offspring, but as I said in my original post I am breeding brother and sister together who are both his offspring (which was your second choice), so you and I are on the same page here: both my fish carry the xanthic gene!

Bas Pels
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Re: Xanthism

Post by Bas Pels » Wed Sep 10, 2008 7:41 am

To get to the second and third queries, did anyone ever hear of fish become xantistic after getting sexually mature?

as far as I know, citrinellum and labiatum, but also the pink fenestratus change color around 15 cm - 6 inches

Petenia spelndida has approx 50 % xantistic around 5 cm - 2 incheds

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illustrator
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Re: Xanthism

Post by illustrator » Wed Sep 10, 2008 8:04 am

corrected

Bluejax
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Re: Xanthism

Post by Bluejax » Wed Sep 10, 2008 10:00 am

I know of a xanthic Parachromis friedrichstahlii:

http://indycichlids.com/Xanthic.html

http://www.monsterfishkeepers.com/forum ... hp?t=67212

Not sure if these are the same fish

ia246
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Re: Xanthism

Post by ia246 » Mon Sep 15, 2008 9:01 am

I thought it was about time I raised my head in this debate - I am Bluejax's co-conspirator in the xanthic jag production line (the female of the pair belonging to me)...

Neither I nor Bluejax intend to sell the fish produced from this spawn as normal jags - if and when we do pass any on that hobbyist will be completely informed of what fish they are buying.

I agree the danger in this process is that a potential rogue gene is being released, however as bluejax said this gene is already in circulation in the UK captive bred jag population.

However, most importantly I, like Bluejax, am very keen to learn more about the inheritance of xanthism in jags. I have fish from a xanthic carrier pair that are at biggest pushing 4 inches long. So far they look like normal jags (though their yellow background is VERY yellow/more metallic golden - I will post a picture if I can take a good enough one...). However none have yet been released from my fish room.

I am devoting a lot of tank space because I think it would be interesting to introduce a new colour variant to the hobby - especially in light of this colour variant NOT being line bred but a spontaneous occurance.

Is there anybody who has raised fish that have 'turned xanthic' upon reaching maturity?

Bas Pels
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Re: Xanthism

Post by Bas Pels » Mon Sep 15, 2008 10:10 am

IA246

thank you for your comments

besides, I thought both of you were in the USA; between me and the UK there is only the pond

PsYcHoTiC_MaDmAn
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Re: Xanthism

Post by PsYcHoTiC_MaDmAn » Mon Sep 15, 2008 7:17 pm

Bas Pels wrote:IA246

thank you for your comments

besides, I thought both of you were in the USA; between me and the UK there is only the pond
completely off topic, but when you mentioned just across the pond I remembered this screen shot I took a while back
Image
Live in the UK?
Interested In Cichlids??
Then join the British Cichlid Association

Bluejax
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Re: Xanthism

Post by Bluejax » Tue Sep 16, 2008 3:58 am

lol

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Willem Heijns
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Re: Xanthism

Post by Willem Heijns » Tue Sep 16, 2008 4:19 am

here's some interesting reading on the mechanism and (behavioral) consequences of xantism and other forms of colour polymorphism in cichlid fishes:

Barlow, G.W. 1973. Competition between color morphs of the polychromatic Midas cichlid Cichlasoma citrinellum. Am.Ass.Adv.Sci. 179: 806-807
Barlow, G.W. 1983. The benefits of being gold: Behavioral consequences of polychromatism in the Midas cichlid (Cichlasoma citrinellum). Env.Biol.Fish. 8: 235-247
Barlow, G.W. 1983. Do gold Midas cichlid fish win fights because of their color, or because they lack normal coloration? A logistic solution. Behav.Ecol.Sociobiol. 13: 197-204
Barlow, G.W. & P.J.Ballin. 1976. Predicting and assessing dominance from size and coloration in the polychromatic Midas cichlid. Anim.Behav. 24: 793-813
Barlow, G.W. & W.Rogers. 1978. Female Midas cichlids’ choice of mate in relation to parents’ and to own color. Biol.Behav. 3: 137-145
Barlow, G.W., W.Rogers & R.C.Cappeto. 1977. Incompatibility and assortative mating in the Midas cichlid. Behav.Ecol.Sociobiol. 2: 49-59
Dickman, M.C., M.Schliwa & G.W.Barlow. 1988. Melanophore death and disappearance produces color metamorphosis in the polychromatic Midas cichlid (Cichlasoma citrinellum). Cell Tissue Res. 253: 9-14
McKaye, K.R. 1980. Seasonality in habitat selection by the gold colour morph of Cichlasoma citrinellum and its relevance to sympatric speciation in the family Cichlidae. Env.Biol.Fish 5(1): 75-78
McKaye, K.R. & G.W.Barlow. 1976. Competition between color morphs of the Midas cichlid Cichlasoma citrinellum in lake Jiloá, Nicaragaua. In: T.B.Thorson (ed.) Investigations of the ichthyofauna of Nicaraguan lakes: 465-475
Webber, R., G.W.Barlow & A.H.Brush. 1973. Pigments of a color polymorphism in a cichlid fish. Comp.Biochem.Physiol. 44B: 1127-1135

I'm sorry not to be able to refer to any articles on Parachromis managuensis in this respect. on top of that, xantism (or another form of colour polymorphism) is also shown by Parachromis dovii (unknown source) and by Herichtys minckleyi (personal observation).

I hope this helps in gaining insight into this interesting phenomenon.
Slàinte mhath!

Uilleam

Bluejax
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Re: Xanthism

Post by Bluejax » Tue Sep 16, 2008 8:20 am

Thanks for providing these references. I was particularly interested to read about the physiological process of melanin loss in Midas cichlids. It would appear to be similar in Jags, as from what I gather, the male xanthic was originally normal in appearance as a youngster before it started to turn yellow. In earlier pictures of the adult fish you can still see a few residual areas of black.

bolty
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Re: Xanthism

Post by bolty » Sun Oct 19, 2014 4:57 pm

I no its an old thread but thats my pic! ummmmmm .........................

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