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Thread: Inheritance of long fins in koi

  1. #91
    Honmei ricshaw's Avatar
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    Quote Originally Posted by JasPR View Post
    ??? sure there are! That is WHy we have terms in judging for 'looks' in kohaku plate arrangements. Unless I misunderstand or misread you posts?
    I give you the tancho, the maruten, the sakai classic three step. All examples of repeating piebald patterns. And my theory is that they are not as rare as our culling stories suggest. It is just that there are so many other types and patternspossibilities within a 150,000 windowed roulette wheel that only a small percentage are going to come up--- leucistic, red color mutation ---AND---- maruten pattern gene. JR
    What about the Red Cap Oranda?



    I would think that there is an example of a "gene set" in goldfish.

  2. #92
    Oyagoi mrbradleybradley's Avatar
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    Quote Originally Posted by JasPR View Post
    ??? sure there are! That is WHy we have terms in judging for 'looks' in kohaku plate arrangements. Unless I misunderstand or misread you posts?

    I give you the tancho, the maruten, the sakai classic three step. All examples of repeating piebald patterns. And my theory is that they are not as rare as our culling stories suggest. It is just that there are so many other types and patternspossibilities within a 150,000 windowed roulette wheel that only a small percentage are going to come up--- leucistic, red color mutation ---AND---- maruten pattern gene. JR
    Yes JR, we are in agreement. A misread or poorly written.

  3. #93
    Nisai
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    Quote Originally Posted by JasPR View Post
    Hi Boris,
    No I definitely didn't want to sound the least but insulting as these typed responses can lead readers to see and hear things not meant! Appreciate your objectivity and understanding.
    I was really referring to the distribution of the red pattern on the kohaku type off spring. Ad you probably know the pedigree horse patterns of piebald are extremely well documented (tobiano, sabino, overo etc) and are even given names and their gene pools protected to the extreme. In koi, the first patterns on kohaku forerunners were really a spotting above and below the lateral line. And early breeders and later judging standards would penalize individual fish that showed pattern on the belly. Over time the pattern was stabilized via selective breeding and ruthless culling. Today we have reasonable fixed piebald patterns that are repeated as two, three and four steps. And the secondary hi spotting is less and less with some plastic surgery in the young removing the last vestiges of random expression.
    The density of those spots or plates are also deeper and stronger a gene expression in the higher quality genes. Even then, some individuals will loss expression of pattern almost overnight.
    Best, JR
    Jim, in this post you gave some interesting for me data how koi patterns changed in generations. There are some visible results but there is no complete resulting uniformity. This is typical for quantitative traits. Why I put special attention on this kind of traits? Since there is frequent opinion that genetics is all about Mendel’s principles and Punnett’s squares. Yes, this is an important part of genetics, but only part of it. I do not compile any lexicon; I simply try to explain some points in more details. Also this information is in addition to PDF presentation which I posted earlier. Therefore I attached it below again.

    So, all morphological traits may be divided to two large groups according to the character of their inheritance: qualitative and quantitative.

    The qualitative traits have the following main features:
    - Have alternative variability, which manifests through appearance of discrete phenotypic classes
    - Are determined by a relatively low number of genes
    - Their manifestation usually does not depend on environmental conditions
    - They are inherited according to Mendel's principles

    As I described in presentation depending on the number of genes classical Mendelian segregations or their modification are usually observed.

    The other main type of traits - quantitative traits are characterized by the following features:
    - Have continuous variation
    - Do not have discrete phenotypic classes but are expressed by certain numerical value
    - Are determined by large number of genes
    - Manifestation of many quantitative traits depends on environmental conditions

    As mentioned above, quantitative traits are characterized by continuous variation. Most quantitative traits have a normal distribution, which is expressed graphically as a smooth curve with a symmetrical location of frequencies decreasing towards both sides from a mean value (bell-shaped curve).

    The quantitative traits are under control of many genes with additive action. Because many genes are involved, inheritance of this type is often called polygenic. Each of such genes may have either an additive allele, which contributes a set amount to the phenotype, or nonadditive allele, which does not contribute quantitatively to the phenotype. The resulting phenotype of a given individual depends on the ratio of additive and non-additive alleles in the genome.


    When we started to measure variability of red coverage in white-red fish we identified that this trait has continuous variation and each fish has numerical value of red coverage. That is features which are typical for quantitative traits. Distribution is not normal, it is shifted but this can be explained by influence of some factors. So, if we have quantitative trait and continuous variation will the selection work? Yes it will, but there are some specifics.


    There are two main types of artificial selection: directional and stabilizing. In attached figures you can see scheme of both types of selection for some quantitative trait. In first figure you can see scheme of directional selection. In this case, among animals of the parental generation, individuals having the best values of trait (according to the selectional goal) are selected for breeding. As a result of directional selection (if it is successful), the mean value of the trait shifts towards the chosen direction, that is mean value of trait in offspring generation is higher than mean value of trait in parental generation (Xo>Xp, see Figure). This scheme is only for one generation but selection can be performed in many consecutive generations and mean value of trait will be shifted further and further in needed direction. In our study we found that mean coverage of red in white-red fish in our case is pretty low. It may be suggested that in high quality bloodlines of Kohaku mean value of coverage during many consecutive generations shifted towards increased of coverage. Nevertheless, since this trait is quantitative, some variability remains.


    Another form of artificial selection is stabilizing selection. In the case of stabilizing selection the animals with values of trait close to the mean value for the group are selected for breeding as shown in corresponding attached figure. This results in decreasing variability for this trait (you can see in figure that range of distribution in offspring generation is more narrow) but the mean value of trait remains the same (Xo = Xp, see Figure). Again, this scheme is for one generation of selection. In consecutive generation of stabilizing selection the range of variability can become smaller and smaller but nevertheless some variability of trait will remain.


    As I mentioned in the previous post, we evaluated quantitatively only red coverage but the value of fish depends not only on rate of coverage but on location of patches. This trait is also very variable since spots and patches can appear on different parts of the body. And it is obvious that this trait is also quantitative. Intensity of red patches is also quantitative trait.

    Jim noted that location of red patches moved towards dorsal part of the fish body. It can be result of directional selection. But also he mentioned some decrease in variability which is typical for stabilizing selection. There is possibility for some combined types of selection, half-directional, and half-stabilizing. And also selection can be directional for several generations and later become stabilizing.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  4. #94
    Daihonmei
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    Excellent and thanks, I'm sure the group reading this thread appreciates it.
    Best, Jim R

  5. #95
    Daihonmei
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    'swimming' back to the original subject, this the look and body type, eye and barbel type ( not the color quality and pattern necessarily) that I favor for a longfin 'dragon' carp.

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