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posted by Fnord666 on Tuesday February 06 2018, @03:49PM   Printer-friendly
from the you-say-crayfish-I-say-crawfish dept.

No one knows exactly when the clones first appeared, but humans only became aware of them in the early 2000s.

It was a German aquarium owner who first brought it to scientists' attention. In 1995, he had acquired a bag of "Texas crayfish" from an American pet trader, only to find his tank inexplicably filling up with the creatures. They were all, it turns out, clones. Sometime, somewhere, the biological rule that making baby crayfish required a mama crayfish and papa crayfish was no longer inviolate. The eggs of the hobbyist's all-female crayfish did not need to be fertilized. They simply grew into copies of their "mother"—in a process known as parthenogenesis.

Crayfish specialists were astonished. No one had seen anything like it. But the proof was before their eyes and in 2003, scientists dubbed the creatures marbled crayfish, or Marmorkreb in German.

https://www.theatlantic.com/science/archive/2018/02/attack-of-the-crayfish-clones/552236/


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  • (Score: 2) by c0lo on Tuesday February 06 2018, @07:20PM (2 children)

    by c0lo (156) Subscriber Badge on Tuesday February 06 2018, @07:20PM (#634047) Journal

    What exactly do you require to use the term female?

    Sexual reproduction with the need of a male sex to produce descendants. But...

    While we are at it, what sex is attributed to the well known parthenogenesis lizards (amongst other species)?

    ... further reading shows that the above definition is too simplistic (so thanks for making me read further.
    I suspect that you'll be pleased to hear that parthenogenesis doesn't necessary produce female only descendants [wikipedia.org] - so "the future is female" is... mmm... greatly exaggerated? (especially when a low genetic diversity means that species extinction due to an illness is almost a certitude on long terms)

    Also, you do realize that there are many polyploid species [wikipedia.org], being triploid doesn't negate sex.

    I'm curious, so I'll be grateful for any detailed study about sexual reproduction in triploids that maintains the triplod trait as a species constant

    The line of my thinking - chances are the offspring to show a dispersion between diploid and tetraploid on different chromosomes, with an average 50% of chromosomes in triplicate, 25% in pairs and 25% chromosomes in tetraploid state in the first generation (meiosis II produces haploids and diploids with equal frequency)
    The chances of "all chromosomes in triplicate" is (1/2)N, where N is the number of chromosomes. To have a pure triiploid species using sexual reproduction exclusively would require:
    1. any non-triploid chromosome in the set is a death warrant (otherwise you'll never see a pure triploid species)
    2. a small number of chromosomes (and thus a non-infinitesimal chance of all-chromosome triploids) and/or a huge number of offspring so the (1/2)N chance still offer chances of some viable descendants. E.g. 20 chromosomes will result in a "all triploid" configuration with a chance of 1 in a million viability.

    --
    https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
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  • (Score: 2) by insanumingenium on Tuesday February 06 2018, @08:22PM (1 child)

    by insanumingenium (4824) on Tuesday February 06 2018, @08:22PM (#634070) Journal
    Did you happen to notice that while I did cherry pick the whiptail lizards, the paragraph you are referencing actually directly contradicts you.

    In polyploid obligate parthenogens like the whiptail lizard, all the offspring are female.[19]

    Let's see

    polyploid - check
    obligate parthogens - no males fo this species exist - check

    You want a polyploid that breeds true, take one of my favorites The California Redwood [wikipedia.org], it is a hexaploid the reproduces sexually. If you want a triploid in particular, you are correct that it doesn't usually breed true, breeding is an integer process (usually, though some fungi are really weird), and three into two makes awkward math.

    Also, in case I haven't beat this horse enough, and since you seem to like wikipedia as a source, please see here for the definition of female [wikipedia.org]

    • (Score: 2) by c0lo on Tuesday February 06 2018, @11:13PM

      by c0lo (156) Subscriber Badge on Tuesday February 06 2018, @11:13PM (#634166) Journal

      You want a polyploid that breeds true

      No, I wanted an example ofa pure triploid with sexual repro.
      Examples of even-ploidy reproducing sexually are quite common in the plant world.

      --
      https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford