Congrat's on the brood! How long have you had the female?
Black is dominant in most cases. The base color could go either way, silver or gold or it may revert to green and sometimes even blue... or all of the above. We're always dealing with mutts at the domestic strain level, so there are no absolutes in regards to dominant traits.
The waiting game is torture sometimes but it keeps things interesting.
Actually, there are some absolutes in regards to dominance of color traits. There are also certain general patterns to expect with particular traits regardless of species. I don't work with Mollies, not sure that anyone has done any serious genetic work with them since we lost Dr. Norton. (There is a difference between selectively breeding for traits and actually learning how those traits are passed on.)
Any genes that produce black are invariably dominant, though they would be better described as partially dominant. One can usually tell homozygous individuals by the greater degree of coverage by the black pigment. Marble Molly fry often start out completely black, then modify to a marble pattern as they grow. If all your fry are black, then at least one parent was homozygous for black or marble. In your case, that would have to have been the mother.
Silver on Mollies is actually a type of color suppression gene. These are usually recessives (albino is the best known example), though they can also be partial dominants. I've never seen Silver Mollies that weren't breeding true (usually a sign of a recessive gene), but I've never taken the time to try and outcross them with normal or other forms of Mollies.
Gold color on Mollies, however, I'm not sure about. This is a pigment increasing gene, and these are usually dominants or partial dominants, like the black Molly, or the Red Swordtail. So the percentage of fry that come out with gold color should be dependent on whether the mother was homozygous or heterozygous. If the first, then she would have given all the fry a gene for gold color, and likely they will all turn out to be Gold Dust like her. If she was heterozygous, then only half will be Gold Dust, and the other half will be normal Marble Mollies. Probably not Silver Marbles; as noted before, I'm pretty sure that gene is recessive.
To be honest, though, I would want some more information before assuming that the Silver male was the one that mated with the Gold Dust female. Is this her first drop after being with him? How long between the time she was introduced to him and the fry drop? Or was she a known virgin? If this is her first drop since they've been together, it's still possible that she was already hit by an unknown male before being introduced, unless she is a fish you've raised as a virgin.
I would be far more interested to see how the next batch comes out.
Very interesting stuff! In my experience, with pure species we can have absolutes. In mutts at the commercial level there are very few, if any, in the color genetics category and very few in fancy finnage. There are too many factors to reach standardized conclusions. One gene behaving differently as expressed with, or upon, a gene inherited from another species, throws the whole rule book out the window.
Years ago, I had someone argue with me up and down that 'dalmation' mollies are not born white with black spots. I had dozens of fry of various ages in my tank at the time so it was easy enough to make the point. Yet I've owned 'marbles' that behave just as you describe.
It has been said for decades that you won't find black on a red-eye 'Swordtail' - we saw pictures of that very thing a couple of issues ago in Livebearers.
This is what makes domestics fun and frustrating to play with, but it also makes them interesting to discuss.
Gold in P. latipinna is recessive to wild coloration but it's dominant in Sphenops domestic strains against any color I've tried. The pattern isn't dominant but the gold is almost always there somewhere. The gold can come from Sphenops, Latipinna or Velifera and Sphenops expresses an entirely different type. The gold in Latipinna is determined through homozygosity for a recessive allele at a single autosomal gene. [R.A. Angus & P.D. Blanchard]. However, most 'Gold Dust' mollies are bred from Sphenops-type fish. When we try to bring a Sphenops Gold Dust into a sailfin line, we often end up with more black (marble), and the gold is often the metalic latipinna gold as opposed to the bright Sphenops gold, indicating different genetics at work.
It boggles the mind, which is why I didn't go into all that and make our poster throw algae wafers at me while making nerd faces...LOL. Thanks for adding your expertise, I enjoy reading about it and it's often difficult to find specific genetic information.
Nanodan, I would expect the fry to change as they mature. There are many strains that start out one color and the pattern alters as they get larger. Given the time frame, it is likely that your silver male did father the spawn, so it should be interesting to see what they grow into!
Melody, Black pigment on Albino Swordtails was known in the late 60s/early 70s, as Joanne Norton wrote about them in The Aquarium magazine. I don't know of anyone with real experience who would claim that black pigment can't exist on Albino Swords (all red eyed sword strains are homozygous for the albino gene; not necessarily true with mollies). However, the black pigment was invariably cancerous, as it is on the so-called "new" Platin Orange Swords out of Germany (these fish are just a remake of the Red Coral Swords using a more orange form rather than the usual red). This made the fish desireable for cancer research, and the gene for cancer in swordtails was isolated as a result. The black pigment on an albino is always an abnormal form, not the normal melanic pigments that form stripes and color the eyes.
I've been studying the genetics of domestic swords for decades, and I repeat, it is different from simply practicing selective breeding. I spend more time taking strains apart than putting them together. I have not worked with Mollies, and right now I doubt that anyone has taken the trouble to isolate the genes that produce certain traits, so it's a pure guessing game. Most of the traits of Swords, however, can be identified and accurate predictions made.
The fact that a fish is a "mutt" doesn't mean that it isn't subject to the genes that it carries. You just have to learn what they are to predict the results. In Xiphophorus, the genes traded between Platy and Sword were figured out over 50 years ago when real scientists were working on them. In Poecilia the work has been done mostly by amateurs, and poorly so far as I can tell.
To predict any genetic outcome with certainty, we need to know what genes or combination thereof we're dealing with. Without a lab, we can't do that. Each fish can be a different combination of genes when we don't know the ancestry. Scientists deal with known entities, that's what labs are for. Hobbyists deal with whatever a store hands them.
We all have our experiences, thanks for sharing yours. I bet I could find 10 people in 24 hours flat who disagreed with us both and make a very good arguement for it. Thankfully, arguing doesn't interest me. Forums are all about sharing and discussing, THAT interests me. Nobody will every be truly advanced without an open mind. Thanks again!
Hi Dan, I have been breeding mollies for a few years now , have never bred the gold dust strain though. Have been breeding Cremecicle mollies ,Black and marble sailfins and Koi mollies ,and have found that the cremcicle mollies do breed young that carry some black .Not all of their young come out solid gold like their parents, some have black in their tails and body. Below is a picture of a solid black and a young Cremcicle molly.I have not yet seen a young molly change color as it got older ,in other words “what you see is what you get” When you mate two different strains and colors of fish together you can only expect to get the dominate color, in this case black
I don't know what's up with the formatting here, but I can only read part of your post so forgive me if I've missed something. You have me curious - what is a 'Koi' Molly? I'm not poised with a 'gotcha' or anything, I've just never heard the term as it applies to Mollies. Do you have a picture?
I have not been arguing, only correcting errors, such as:
The gold in Latipinna is determined through homozygosity for a recessive allele at a single autosomal gene. [R.A. Angus & P.D. Blanchard].
Well, I found the article by Angus and Blanchard, and they did NOT state the inheritance of Gold in latipinna mollies as a recessive. They instead stated that the heterozygous state resulted in a higher than normal percentage of xanthophores, but that these were covered by the incomplete dominance of the normal melanophore pattern. This coincides with my own observations crossing a gold form individual of Etroplus maculatus with a wild form. The heterozygous form does have an increase in xanthophores, but only in the homozygous state does it override the production of the normal melanophores as well.
The basic effect is that a heterozygous fish looks more yellowish than a normal wild individual, but still has all the normal black pigments. This is different from a recessive that requires a fully homozygous state to be expressed to any degree.
Thanks for that reference BTW, it was very useful as it verified something that I believed, but had no external reference to point to as a repeat pattern for identifying the genes involved.
And figuring out the relevant genetic makeup of a fish doesn't require a lab; it only requires adherence to the scientific method. Joanne Norton didn't have a lab, she had a fishroom. But she understood keeping accurate data. Again, that's not an argument, but another corrective qualification of your overstatement.