Question about filial generations...

J

jbuncc

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I've been meaning to ask this question for a while, and figured I'd get a little traffic into this forum while simultaneously getting an education :nuts:

I'm confused about how to label offspring if the filial generations are not the same. For example, if I were to breed an F9 to an F4, what would the resulting babies be? Would they be F10's or F5's or something completely different?

Also, is there any difference in the answer if you breed an F3 to a WC animal (obviously of the Pth generation).

Thanks for any insight you can offer!
JB
 
The filial number denotes the number of generations the animal is removed from its wild ancestors.

When determining the filial number for offspring with parents having different numbers, you only consider the parent that is closest to it's wild ancestors, in other words, the parent with the lowest filial number.

For example:
F6 x F3 = F2
F3 x F4 = F4
F5 x WC = F1

Since you want the number of generations removed from the wild, you will of course find wild ancestors sooner in the family tree from the parent with the lower filial number. Regardless of how high the other parent's number is, this is still where the bloodline of the offspring meets the wild ancestors, so this is the number of generations it is removed from them.
 
Clay,

I was confused a little bit on your numbering.

"For example:
F6 x F3 = F2"

Your other numbers made since, but this one didn't. If you were breeding an F6 to an F3, wouldn't the resulting offspring be F4 instead of F2?
 
You are absolutely right Rob, I even read over the post and didn't catch my error before hitting submit.

Glad you were paying closer attention than I was.
The consise version though is to take the parent with the lowest filial number and add one to it for the offspring.

Thanks for the correction, don't want to confuse anyone.
 
F6, F3, etc are filial numbers. These are a means of tracking generations.
In this case F3 would denote the 3rd generation of offspring decended from the wild caught founding parents.
An F1 animal would have either one or both parents being wild caught. The offspring of two of those siblings would be F2 because they are the second generation from the wild caught parents.
The number following the F tells you how far back you can go to find wild caught parent(s) in the snakes history.

I believe the rest of the details of calculating the filial number were adequately described above.
 
I respect this information but...

(of course there was going to be a but :argue: ) can't there be a more simple way to put these numbers in check? I'd feel bad about outcrossing an F6 with an f1 and calling the offspring F2. It would seem division would be in order to come up with an appropriate filial number in this case. Or at LEAST an asterik (Oh, I hate that I can't edit spelling!:uhh:) to explain the result. But glad to have this cleared up, even if I don't "like" the answer!
 
But if you bred an F1 and an F6, the appropriate number for the offspring would be F2. This is the reason for filial numbers, to determine how far back you go into an animals bloodline to find the founder stock, in this case the original WC animals.
If you instead split the difference between the numbers, the resulting number for the offspring would have no meaning, since it would not denote anything. It would be bypassing the purpose of the filial number to begin with.
 
Filial generations

I'm a little confused. I was under the impression that P, F1, F2... and so on were references for relatedness and had nothing to do with generations removed from the wild. I thought the filial generations were ways to demonstrate genetic connections between related animals. For example, the "P" (parent) generation breeds together to produce the F1 generation. The F1 (siblings) breed together to produce F2s. Each successive generation is selfed or bred together to produce the next filial generation. Breeding the F1 babies from two unrelated pairs of animals would therefore produce F1s because there is no genetic connection between the offspring of parent pair "A" and "B". The F1 offspring would in essence become a new P generation. Can anyone comment on this? I think the generational indicator may be a misapplication of the original definition.
 
The use of filial generations as you described is correct within a closed breeding group. It is used just as you described.
However, we also use the same notation to clarify generations removed from the wild across the entire hobby.
You may have a group of gray bands for instance that you have been selectively breeding for several generations for a given trait. You may be up to F5 within your group. If I were to purchase one of these animals to add to my group the F5 is meaningless to me since I will revert back to F1 with the first breeding in my group.
On the other hand if I'm looking for some fresh blood to add to my group of alterna and I want some CB offspring from WC parents then that is when the other use of the terms comes in. This is the usage of the term as seen in the classifieds when F1 alterna are offered for sale. In this case the F1 is important information in that it describes a state that cannot be changed. The snake is one generation removed from the wild and nothing can alter that.
If however I buy the F5 from your group and another from a different group and breed these to produce F1s then it creates confusion if I advertise them as F1s. They are F1s within my collection, but that has no meaning at all once they become a part of another breeding group, whereas how fresh the bloodline is holds its importance.

Whether scientifically speaking this is correct I do not know. Regardless of that fact, filial generations are used in this fashion and will continue to be so.
Just as the term co-dominate is used often in reference to various ball python morphs even though the term is incorrect scientifically. It's simply too late to change the usage at this point.
Since the vast majority of people involved in the hobby only encounter the filial numbers in the classifieds and in that case it is referring to generations removed from the wild, that it the method I used to answer the question so as to avoid confusion.
 
I did a little research since my last post and it seems that my recollection of filial and parental terminologies was correct. Filial generations have nothing to do with generations removed from the wild (unless the wild caught animals produce babies that are bred back to one another for successive generations). I've often heard folks say "F1 from WC" when they're selling hatchling alterna (to continue on your example). If it was indeed the case that F1 represented the first generation removed from WC animals "F1 from WC" would be redundant. Folks would just say "F1". "F1 from WC" simply indicates that the hatchlings being offered for sale were produced by a P generation that was collected from the wild and that the babies are all related. The misapplication of F1, F2, F3... doesn't change the meaning of the terms, it just confuses everyones' understanding of it. If a herp hobbyist is concerned with acquiring animals with close ties to WC individuals they need to understand that a filial term (in this case F1) is not at all an indicator of the characteristic. F1, F2, F3 are simply ways to designate progressive generations of inbreeding. That's why the term is used so often with genetic traits. Lines are purposefully inbred to determine the heritability and types of heritabilities for particular traits. The designations are maintained so as to keep track of relatedness and allow or prohibit inbreeding. According to the actual and scientific definitions of parental and filial terms, it is possible to have a 6th generation captive that is an F1. If it were true that F1, F2 etc. could only be applied to animals with the corresponding number of generational separations from wild caught stock, the term could only be used on species where that fact is traceable. That would exclude all but those species herp lovers could have a personal knowledge of collecting. There would be no such thing as F1 Womas or F2 Olive pythons (which obviously is not the case). While perusing the internet is easy to see that folks misapply the terms. Even if the vast majority of herp enthusiasts misuse the terms it still doesn't make the use correct. It would be accurate to refer to animals with a 2 generation separation from wild caught stock as "2nd generation captives", but not as "F2s".
 
Your definition of filial generations is correct, I stated it was in my last post.
Regardless, it is still used within the hobby to denote generations removed from the wild as well. The fact that this is an incorrect application of the term is basically irrelevant at this point, it is ingrained in the vocabulary of hobbyists.
The vast majority of hobbyists are at best merely armchair scientists. I could have answered the original question with the actual scientific definition of the term, but that is not how they encounter the term on a regular basis and therefore doesn't actually answer their question at all.
Unfortunately it's one of those cases where the incorrect usage of a scientific term has become accepted within the hobbyist community as a whole. It has in effect, as far as laymen are concerned, become correct. Just as the first leucistic leopard geckos were not leucistic at all, and pastel ball pythons are not actually co-dominate. Pastels will always be known to the hobbyist as co-dom because of an initial misuse of the term. Most of these hobbyists have never heard the correct term incomplete dominance. Likewise to the hobbyist who only sees the term F2 in the classifieds it will continue to refer to generations removed from the wild because this is the definition of the term that affects them difectly.
We can champion the correct usage of scientific terms all we want, but it will make little difference to the hobbyists who get the majority of their "scientific" information from Reptiles magazine.
Correct or not that is what the term has come to mean in the amatuer sector, which is what we are dealing with. It is now a term that, for all intents and purposes, has two definitions, even though you'll never find but one of them in a text book.
 
I realize that the filial generations are incorrectly used within the hobby to reference generations. I would disagree that that situation is uncorrectable. A misunderstanding like this can only persist if no one shares the correct information. I'd be willing to bet that most misinformed keepers would be open to learning the correct terminology. The vast majority of herpers have a passion for what they do and I'm often amazed at the extent of education keepers can provide for themselves simply because of that passion. I just wanted to make sure that there was some mention of the correct usage in this thread so that anyone searching for the definitions of "filial generations" got the facts and not the persistent misconceptions.
 
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