Your questions/concerns are valid. A paternity is simpler, and has been currently available technology wise for a couple of years. I don't know any company offering it as a standard service though.
Quick and dirty answer-if you are breeding the females to a homozygous male(and the morph is well documented, proven to be viable, and has had no suprises elsewhere), then the paternity test is accurate
this post is very long winded and comes back to point at the end.
However, if you are dealing with a new morph, undocumented/low produced doubles-triples-or more, mutations with other effects to the body other than pattern or color. The only way to absolutely confirm is to breed it and produce living proof. The next statements are very very very broad as you could write several text books, college classes, and several Ph D. worthy projects out of what is really needed to prove the following or at least outline it correctly.
There are all sorts of other things at play into genetics, and embrionic development that are not cut and dry. So you could produce a het, that tests positive as being a het genotypically, but due to other factors(such as embryonic lethality, floxed genes, down regulation, sympathetic factors, secondary mutation) you never see a mutant/visual morph produced from it. We have a few lines of mice like this that the lab I am in works with. We have to bring the gene in through the male side or it is embryonically lethal. We also have other lines of mice that when we breed het to het, we only see the mutation if a second and different gene mutation is there that allows the first mutation to express.
Or (broad generalization here) in pied, you have a 90% and a 10% white-whats the difference? They are both the same genotype, however, one animals ability to produce normal coloration and pattern was severely reduced and the other wasn't. This could(broad speculations here) be due to how early in development that the cells/hormones/chemicals that derive normal color are blocked. Also some pieds the "normal" areas are normal, other pieds have "normal areas" coloration and pattern that are really aberrant. Is this(broad speculation) the area of epithelial tissue that was effected genetically and going to be white, but then surrounding epithelial cells had a sympathetic effect in embryonic development and tried to "fix" the area?
In embryology the parents genes are a starting point, and external factors can shift/effect what happens next until the point of birth. In animals that carry the babies full term things like diet and the toxins contained within, inhaled pollutants, depression-which effects hormones, micronutrients all can affect the outcome a baby. Well in reptiles that lay eggs we see all of the above but also then through in temperature, humidity of the eggs environment, co2/o2 saturation in the eggs environment can also shift the outcome of a baby.
Also in ball pythons, corns, and leopard geckos there is a lot of mutations that have names that are super similiar, and may be the same mutation but with a slightly varied set of background dna or modifier genes. So our human definitions/names may be causing us to unduly put things into wrong categories, or incorrectly relate some animals. Like pied and calico, both have something that causes scales to be white, it is organized in pied and dispersed in calico. It may be the same mechanism with a different secondary change , or it may be completely different mechanism that shows up as similiar phenotypes
Also random mutation can pop up at anytime that does who knows what, and isn't always visable/phenotypic so we can never rule that out. So you may have a cut and dry breeding that suddenly turns out new looking offspring, or suddenly blocks the mutation that has been passed down unchanged for 10 generations.
For example: I have a massive but young female boa that has this great big old head that reminds me of a bulldog. I breed her every year to a male albino that has very thin and refined features, but yet most of the babies come out with block heads. So I cannot say whether the animals will produce block headed babies 2 or 10 or 40 generations from now-only that I bet I get a bunch of block heads this year.(new co-dom right LOL) Although rattlesnake guys have well documented that a baby EBD head will grow proportionally to what you are feeding it. Lots of little meals equals a little head, infrequent large meals and you get a big head.
So just becuase you breed a pied to a normal does not Absolutely 100% guarantee that you will have het offspring that can in turn produce pieds. However, being a snake person, and a person of odds, I would be shocked if any of the above variables happened and you didn't produce 100% hets. Pieds have been bred enough and in enough species(people, horses, several species of birds, a couple species of snake, lots of rodents) that we are almost guaranteed that a pied x normal breeding will result in hets that can eventually produce pieds.
Back to the retained sperm issue. In my opinion a mixed litter is very rare on the whole. Yes, we have heard about it, we have also heard about parthenogenisis for a long time, and bicephalic snakes. I have seen multiple examples of both. However, between my own colony and 3 of my closests friends I see almost 600 clutches per year. But if you figure the number of clutches intentionally produced, accidentally produced, and gravid females that are imported and drop of all the species we see. The number of each of these aberrancies is very very small.
However, an easier, and probably less expensive way to go about it is to
stand behind your animals. Keep good records, know what you bred(don't get to the fall of 07 and go what did I breed this girl to last year), keep photos of your babies and sales record so in three years you don't get a reverse scam on you.
Sorry that there is about a million topics in here, I went to the coffee shop just before logging on.LOL
Thanks
ben cole
