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Thread: It keeps getting better and better

  1. #25

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    Quote Originally Posted by [b
    Quote[/b] (tonyc @ Mar. 19 2006,3:45)]... They seem subtly different to me, ...
    Hi,

    judging from your pictures only the leaf apex seems to be totally different. I don't know if this variation can occur in the same species?

    Joachim

  2. #26

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    Hi Rob:

    I know beforehand that you have seen and grown these plants long before i learned to grow them, but would it be possible that a jacquelinae X izumiae combination would yield a plant that looks more than izumiae than Jacquelinae eventhough the majority of the plants from this cross would look more like jacquelinae rather than izumiae. This is based on the laws of probabilities in genetics.

    Gus

  3. #27

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    Hi Gus, I'm really no expert on this. My understanding is that the characteristics of a hybrid follow a binomial distribution with the highest probability that the offspring will bear roughly even characteristics of both parents. However, there is a possibility that it may look almost exactly like one or other parent but the liklihood of that is very small. I think there is a much higher liklihood of someone here making a mistake although I can't imagine how in this particular case. The N. izumiae and N. jac are in entirely different nursery buildings, it's not just a case of someone accidentally placing a plant on the wrong bench or labeling incorrrectly.

    Joachim, there can of course be huge variation in form between plants of the same species. A good example is N. rafflesiana of which there are almost no two identical. However, this seems to apply mainly to lowland species and there is usually much less variation with highland species. I have no field experience with N. izumiae and therefore have little idea opf how much the may vary and whether that variation can include differences in leaf apex. I guess it's possible though.
    Rob Cantley
    Nep Nut in Sri Lanka
    http://www.borneoexotics.com

  4. #28
    Tony Paroubek's Avatar
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    When dealing with a first generation primary hybrid, a cross between two species, the odds that one offspring look almost exactly like one parent is nearly if not completely zero. The genetic material in each hybrid offspring is nearly identical with half coming from one parent and half from the other. So all the hybrid plants end up looking very similar with only minor variation from one another. Now this doesn't mean that they can't be more like one parent than the other, but there will be little significant variation among the hybrid population.

    For kicks.. take two plants from that first generation and sibling cross them. Then you can get theoretically everything from one species to the other with everything in between ;>

    Very simplified layout with a single chromosome pair
    N. izumiae AA 100% x N. jacquelineae BB 100% =
    first generation AB 100%

    first generation AB x first generation AB = mix of:
    second generation AA 25%
    second generation AB 50%
    second generation BB 25%

    give it a try with more chromosome pairs and you can see how 2nd generation the combination possibilities become like the Lotto Drawing! The first generation though doesn't change much.
    Is that a Nepenthes in your pocket or you just happy to see me?

  5. #29

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    lol seems to be right! this was taught in i think 9th or 10th grade at my school with puttnum squares, i think thats how you spell it?
    \"Nepenthes, the Devil's Cup\" - Santos
    Updated 5/27/06 Grow/Want List
    Updated 4/4/06 My Nepenthes Photo Album
    Feel free to call me @: (562)528-6223 - seriously!

  6. #30

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    Hi Tony and Rob:

    You are absolutely right, very clean mendelian genetics. the exact course of events; however, becomes very obscure when we are dealing with several chromosome pairs, then how can we accurately predict the genotype or the phenotype of a hybrid, considering that the chromosomes predicting the sex on Nepenthes for example are not 50%-50% even on a F1 generations when we should predict a more homogeneous gene distribution ?

    Let's hope there was a mix up with the plants to make matters simpler to everyone !

  7. #31
    Tony Paroubek's Avatar
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    Hi Gus,

    Accurately predicting the genotype on primary hybrids is straight forward. Phenotype is another thing altogether as we are all familiar with some species exhibiting more dominance than another. When dealing with previously unknown primary hybrids there is always room for a surprise as you never know for certain how the genes will express themselves in the F1 generation. It is fairly safe to say though that in F1 primary hybrids the range of phenotype differences in the HYBRID population is minimal. Only when you get to F2 and beyond or start mixing different hybrids do you see a much broader range of phenotypes showing up.

    As for the sex determination who knows... Perhaps it is multiple genes? If for example it were 2 genes A and B and in order to be female for example 2 B genes needed to be present. All plants with AA or AB were male. Then the ratio would naturally be about 75% male. On the other hand who can say for certain that the ratio really isn't 50% each? Maybe environmental factors cause more female plants to die in the wild so the ratio is skewed? I could probably come up with another dozen hypothesies too

    Tony
    Is that a Nepenthes in your pocket or you just happy to see me?

  8. #32
    Always a newbie glider14's Avatar
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    AH yes punnunt squares....genetics was one of my favorite untis. but tony said that in the F2 generation you have a 25% AA(izumiae) 25% BB(jacquelineae) and a 50% AB(jaq x izumiae). THIS DOES NOT MEAN YOU WILL HAVE A CHANCE OF GETTING PURE JAQS OR IZUMIAES IF YOU BREED TWO OF THE HYBRIDS!!! it means that 25% will look more like a jaq, or 25% will look more like a izumiae or 50% it will have balanced characteristics (i asked this to my biology teacher and that was what he said). oh ya and 25% is just an estimate. for example if you have 100 seeds 25 will most likely not be the jaq or izumae. and anybody PLEASE feel free to go against what i have said. okay im done
    alex
    Everything is explainable. The seemingly unexplainable is but a result of our insufficient knowledge.- Hans Brewer

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