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  1. #1
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    Default Understanding Filial Generations - for morphers and locality enthusiasts alike!

    There's probably more confusion around this topic, than there is understanding. I even had a lingering question that Warren Booth helped me to understand prior to writing this (indicated below). I thought I'd do a quick write up in case anyone is interested.

    The “F” in F1, F2, F3, etc., stands for “filial”. Filial can be defined as:
    1: of, relating to, or befitting a son or daughter <filial obedience>
    2: having or assuming the relation of a child or offspring

    Each F# is a generation. So F1, F2, F3, etc, are known as “filial generations”, of a particular line.

    Probably the most common misconception about filial generations is that the “F” number denotes how many generations removed from the wild a particular animal is. For example, many believe that an F5 animal is 5 generations removed from the wild. This can be correct, or incorrect, depending on the history of the animal, and its’ ancestors. I’ll explain further, below.

    So, how do you get to “F1”?
    Well, you need the “parents”, or the “P generation”, or “Pth generation”.

    The P generation is two immediately unrelated parents that are bred to each other and produce offspring. The parents can be any combination of WC (wild caught), CB (captive born/born in captivity/farmed), or CBB (captive bred and born).

    All of the following are examples of P x P and would result in F1 babies:
    WC x WC
    WC x CB
    WC x CBB
    CB x CB
    CB x CBB
    CBB x CBB

    Again, any of these examples yield F1 babies as long as the parents are unrelated.

    Once you have F1 babies, they can either be used as “Pth generation” animals to start a new line, or they can be bred to each other to produce F2’s.

    F2’s are produced by pairing F1’s OF THE SAME LINE.

    For example, if you have four animals, labeled: A, B, C, and D, and you pair them as follows:
    A x B
    and
    C x D

    A x B = F1 (AB line)
    C x D = F1 (CD line)

    Breeding F1 (AB line) x F1 (CD line) = F1 (ABCD line) NOT F2’s!
    However, breeding
    F1 (AB line) x F1 (AB line) = F2 (AB line)
    Similarly, breeding
    F1 (CD line) x F1 (CD line) = F2 (CD line)

    It follows that breeding
    F2 (AB line) x F2 (AB line) = F3 (AB line)
    And
    F2 (CD line) x F2 (CD line) = F3 (CD line)

    Also,
    F2 (AB line) x F2 (CD line) = F1 (ABCD line)

    This can obviously be taken to an extreme to yield F(any number you want), but should be tempered with the need to outcross if offspring are showing deficiencies.

    The following was my only point of confusion, which Warren Booth was kind enough to help me clear up.

    Should you have different filial generations OF THE SAME line, the offspring should be denoted as one filial generation after the mother. For instance, if you have the dam, an F3 AB line and the sire, and F7 AB line, the offspring should be F4 AB line - with full disclosure of the fathers’ F7 status, of course.

    I hope this was helpful and/or informative!

    Thanks,
    jb

  2. #2
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    that's an interesting read, thanks for that!
    i always thought the "F" series were anything after the bloodline begins, like if you bred ab x cd you would get f2s of both parents (an f2 ab line and f2 cd line).
    i understand inbreeding is a common practice in the reptile community (not just for mutations either), but how much is too much? by that i mean what amount of outcrossing is recommended in between line breeding trials?
    also a question if i may, if we're talkin a codom or dominant trait, if you outcross a few times, say 5, for example, then breed one of those "5th generation" snakes to the original first, is that making f2s?

  3. #3
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    I put alot of time into learning the true meaning of Filial Generations

    Here are some Definitions I liked and kept in my records;


    F1, F2, P gen

    Parental generation

    Definition

    noun

    (gene tics F1 F2) The first set of parents crossed in which their genotype is
    the basis for predicting the genotype of their offspring, which in turn, may be crossed (filial generation).



    Supplement

    In parental generation, two individuals are mated or crossed to determine or predict the genotypes of their offspring,
    called first filial generation (or f1 generation).




    Filial generation

    Definition

    noun

    (genetics) Any generation resulting from a genetically controlled mating following parental generation.


    Supplement

    The filial generation is marked with the symbol, F. The filial generations are organized in a sequence of matings such
    that the successive generations after a parental generation is attributed by the symbols F1 (for the first filial generation),
    F2 (for the second filial generation), etc.



    First filial generation

    Definition

    noun

    (genetics) The filial generation comprised of offspring(s) resulting from a cross between strains of distinct genotypes.


    Supplement

    The first filial generation is the generation resulting immediately from a cross of the first set of parents
    (which are designated as the parental or P generation).




    Second filial generation

    Definition

    noun

    (genetics) The filial generation comprised of offspring(s) resulting from mating or genetically crossing two members
    of first filial generation.



    Supplement

    The second filial generation is the result of a cross between two F1 individuals (from F1 generation).

    __________________________________________________ ________________

    Filial generation-F-Labelling & Generation Questions





    Filial generation :

    The offspring of a genetically specified mating: first filial generation (symbol F1), the offspring of parents of contrasting genotypes;
    second filial generation (F2), the offspring of two F1 individuals; third filial generation (F3), fourth filial generation (F4), etc.,
    the offspring in succeeding generations of continued inbreeding of F1 descendents.


    F2 generation :

    The second filial generation, produced by selfing or intercrossing the F1 gen



    P-generation
    Definition


    (genetics) The first set of parents crossed in which their genotype is the basis for predicting the genotype of their offspring,
    which in turn, may be crossed (filial generation).


    Supplement :

    The "p" stands for parental. Parental generation is the first generation involving two individuals that are mated to fore see or analyze
    the genotypes of their offspring.

    To simplify The "F" generation always refers to inbreeding (same thing as Line breeding)


  4. #4
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    Great info, I was talking about this the other day with someone. I think this will help explain it better then I was doing.

  5. #5
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    Great info JB. Thanks for the post. I think 90% of the people that use the filial generation labels on their animals don't understand all of this.

  6. #6
    jeffreyr Guest

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    Thanks....

  7. #7
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    JB , I was also stumped in the same place that you were - thanks for the clarification.
    > So that means that an F1 male bred back to his mother (Pth generation) would yield F1 babies, right ?

  8. #8
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    Quote Originally Posted by Morgans Boas View Post
    JB , I was also stumped in the same place that you were - thanks for the clarification.
    > So that means that an F1 male bred back to his mother (Pth generation) would yield F1 babies, right ?
    You know, that's an interesting variation of my same question. If I'm reading "Nitram's" post correctly, he had a similar question (using the "original first"). I wonder if it's a different scenario when you go back to the Pth generation, vs the offspring of a particular pairing. IMO, F1 makes the most sense (again, with full disclosure) because either way, it's F1. If you consider both parents as Pth generation, then the babies are F1. Or, if you use the rule Warren gave, they're still F1. So yes, I suppose you're right

    jb

  9. #9
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    I read this in reading about certain plant crossings.


    "German geneticists often describe a backcross of an F1 back to a P1 parent as a F2 cross"

  10. #10
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    I call the White Groups produced from breeding our best 04 WG OT hypo back to his mom F2's, as the mom is also WG in phenotype. All of the babies from these breedings(one litter in 07 and again in 09), hypos and normals alike were WG. Believing this to be a polygenic, line bred trait, and not a single gene mutation, I called them F2's.

    I believe this to be the correct terminology as I understand it.

    Great post, with great info. Thanks JB and Lar!
    Jesse Van Atta

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