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Earth Science

Female Shark Learns To Reproduce Without Males After Years Alone (newscientist.com) 164

Posted by BeauHD from the who-needs-men-anyway dept.
An anonymous reader quotes a report from New Scientist: A female shark separated from her long-term mate has developed the ability to have babies on her own. Leonie the zebra shark (Stegostoma fasciatum) met her male partner at an aquarium in Townsville, Australia, in 1999. They had more than two dozen offspring together before he was moved to another tank in 2012. From then on, Leonie did not have any male contact. But in early 2016, she had three baby sharks. Intrigued, Christine Dudgeon at the University of Queensland in Brisbane, Australia, and her colleagues began fishing for answers. One possibility was that Leonie had been storing sperm from her ex and using it to fertilize her eggs. But genetic testing showed that the babies only carried DNA from their mum, indicating they had been conceived via asexual reproduction. Some vertebrate species have the ability to reproduce asexually even though they normally reproduce sexually. These include certain sharks, turkeys, Komodo dragons, snakes and rays. However, most reports have been in females who have never had male partners. In sharks, asexual reproduction can occur when a female's egg is fertilized by an adjacent cell known as a polar body, Dudgeon says. This also contains the female's genetic material, leading to "extreme inbreeding", she says. "It's not a strategy for surviving many generations because it reduces genetic diversity and adaptability." Nevertheless, it may be necessary at times when males are scarce. "It might be a holding-on mechanism," Dudgeon says. "Mum's genes get passed down from female to female until there are males available to mate with." It's possible that the switch from sexual to asexual reproduction is not that unusual; we just haven't known to look for it, Dudgeon says.
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Female Shark Learns To Reproduce Without Males After Years Alone More

Female Shark Learns To Reproduce Without Males After Years Alone

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  • I know what happened (Score:5, Funny)

    by fph il quozientatore ( 971015 ) on Thursday January 19, 2017 @02:06AM (#53694493)
    It's the Messiah! Bow down before them and adore them!

  • Cue Jeff Goldblum (Score:5, Funny)

    by freeze128 ( 544774 ) on Thursday January 19, 2017 @02:07AM (#53694497)
    "Life... Finds a way."

    • Re:Cue Jeff Goldblum (Score:4, Informative)

      by backslashdot ( 95548 ) on Thursday January 19, 2017 @02:22AM (#53694539)

      Unless you are in the 99.999% of species that went extinct.

      • Re: (Score:2)

        by Calydor ( 739835 )

        And yet life is still here - so life DID find a way.

      • Re:Cue Jeff Goldblum (Score:5, Insightful)

        by silentcoder ( 1241496 ) on Thursday January 19, 2017 @02:38AM (#53694601)

        Life finds a way, life survives - any particular species may not. Life is resilient - but species are not. Indeed it could be argued that life is resilient BECAUSE species are not.

        • Re: (Score:2)

          by zifn4b ( 1040588 )

          Life finds a way, life survives - any particular species may not. Life is resilient - but species are not. Indeed it could be argued that life is resilient BECAUSE species are not.

          Isn't life in this context an abstract concept in the way you're using it? Life to me is the category of things in the universe that all living things are members of. If that's not what you're referring to, how can you make this claim in this way? I'm not trying to disagree but I'm curious if you could refine your statement to have more precise meaning because I am genuinely interested in your thoughts if you are well versed in the subject matter domain.

          • Re:Cue Jeff Goldblum (Score:5, Insightful)

            by silentcoder ( 1241496 ) on Thursday January 19, 2017 @09:30AM (#53695919)

            Life, as a whole has survived every extinction level event that happened -but each has caused massive extinctions. Individual species come and go, as long as they don't all go at once, life persists.
            Life could be reduced to a single species of extremeophile bacteria living around one volcanic vent in the pacific ocean tomorrow... and in a million years the world would, once again, be crawling with many different creatures.
            In fact, the immediate aftermath of mass extinctions tend to be the time when the greatest biodiversity is found. With all the old species gone, practically *anything* can survive - so some really weird creatures evolve and thrive for a while. Then the numbers get big enough for resources to stop being abundant and natural selection kicks in. The worst species start failing and die out.
            After a while you get into an equilibrium state - where every breeding pair of every species only produce, on average, two offspring the go on to breed again. That state lasts until the next major extinction level event.

            The reason life can survive whatever the universe throws at it is because life doesn't rely on any particular species, any of them can be lost - it just needs SOMETHING to survive.

            • Life is just a term for reducing entropy locally by increasing it globally by a greater amount. Given how fond the universe is of increasing entropy, it will keep producing these things.
          • There is something that silentcoder talks about which is confusing, because it doesn't have any meaningful objective existence. But it's not the concept of "life", it's the concept of "species".

            "Species" isn't a characteristic of any living organism - it's something that we project onto two (or more) living organisms. If they're capable of producing fertile offspring (with some caveats for sex errors, and non-sexual organisms), then we humans classify them as being of the same species. The organisms in que

            • Indeed. I once had an illuminating discussion with a creationist who was intelligent (as distinct from an intelligent-crestionist); believed in microevolution, i.e. within each species, but not macroevolution, i.e. from one species into another. He said, as usual, "Where are all the intermediate forms of species evolving to others?" And I replied, as usual, "Well, look at how the horse evolved from Eohippus; we're lucky enough to have a pretty good fossil record of that case." Then he asked, "What makes you
              • Like I said - "species" isn't something that exists for any particular organism. It's a test or concept that can only be applied to groups of individuals - can they interbreed and produce fertile offspring?

                Leaving aside asexually reproducing organisms, every organism is a product of the mating between it's parents, and may have offspring. And for that particular organism, you can't even be sure that it can successfully reproduce if it mated with either or both of it's parents, or any of it's offspring. The

        • Certain particular species seem to be more resilient than others as seen by how long they have been around. Sharks is one of them. Perhaps that trait is one of the reasons why. I wonder if alligators and crocodiles have similar traits? (and other seemingly ancient species)

          • >Certain particular species seem to be more resilient than others as seen by how long they have been around. Sharks is one of them. Perhaps that trait is one of the reasons why. I wonder if alligators and crocodiles have similar traits? (and other seemingly ancient species)

            We don't actually know that. There were crocodilians around with the dinosaurs - but not the same species we have today. In the case of sharks - we've found great white bones from back then, but we don't actually have any proof they we

      • Make the Earth fair again, down with the 0.001%!

    • Re:Cue Jeff Goldblum (Score:5, Informative)

      by Xest ( 935314 ) on Thursday January 19, 2017 @05:32AM (#53695001)

      For anyone wanting to know more, the scientific name for this is parthenogenesis. It's well documented across many species and as usual Wikipedia has an article on it here:

      https://en.wikipedia.org/wiki/... [wikipedia.org]

      Simply put it is indeed a survival mechanism that's more common than we probably realise.

      • Yeah, and it's related in a way to the "life begins at conception" argument. The conversion from haploid (one set of chromosomes) to diploid (two sets of chromosomes) occurs normally when the sperm delivers the second set, then the ovum starts developing and dividing. But these are really two separate phenomena, which are linked by a mechanism which presumably evolved. The first sperm's contact with a specific receptor on the ovum triggers a big influx of calcium into the cell, which causes it to shut down

    • Re: (Score:1)

      by Anonymous Coward

      Jeff is an actor. Crichton is the creator.

  • Cool, but... (Score:5, Funny)

    by slazzy ( 864185 ) on Thursday January 19, 2017 @02:17AM (#53694521) Homepage Journal
    But has she figured out how to grow her own lasers yet?

  • Interesting (Score:1)

    by Anonymous Coward

    I thought this was interesting. Thanks for posting it!

  • Men (Score:1)

    by Anonymous Coward

    If men could reproduce after years of trying alone most slashdotters would be dads.

  • Now, with lasers on their heads!

  • She did what? (Score:5, Funny)

    by irrational_design ( 1895848 ) on Thursday January 19, 2017 @02:28AM (#53694557)

    She _learned_ it did she? Hopefully the same book that taught her about asexual reproduction doesn't have a chapter on lasers.

  • This place is filled with people with the world's most experienced experts on asexual reproduction.

  • War on men (Score:2)

    by Anonymous Coward

    More ammo for the war on men....

  • Doomed I tell you! We are no longer needed at all what-so-ever

    • Re: (Score:2)

      by Hylandr ( 813770 )

      Maybe we can finally shed the dregs of progress and get out to the other planets and stars since they won't seem to need us anymore...

  • ... if this has ever happened to a human, or near-human creature through human history.

    I'm not even trying to make a joke. This genuinely intrigues me.

    What biological mechanisms allow this? And what mechanisms trigger it?

    • Re:I honestly wonder... (Score:4, Insightful)

      by silentcoder ( 1241496 ) on Thursday January 19, 2017 @04:34AM (#53694875)

      The answer is (almost certainly) no. Parthenogeneses has never been observed in humans at all and has never been naturally observed in any mammal in fact. It does occur in some other species (fishes, reptiles and amphibians) but it is apparently impossible in mammals. The only cases in any mammals seen thus far were deliberately done by human intervention using the same types of techniques used for cloning.

      • The only cases in any mammals seen thus far were deliberately done by human intervention using the same types of techniques used for cloning.

        It's been over a decade since I read the story, but pretty sure it was about a whale becoming spontaneously pregnant in isolation, without contact with a male for years.

        • I actually did a google before writing that, to make sure my memory wasn't letting me down - and the only stories I could find were about human-induced parthenogenesis post-dolly using a modification of the same technique.

          If what you're saying is true, then I don't know about it. I did however read quite a few scientists on those stories declare that what they have achieved is considered impossible for mammals, so it seems unlikely.

      • How would you know if you observed it in a human female who was sexually active? In fact, even if it did happen to a woman who had not had contact with any sperm, nobody would believe her.

        • For a start - a simple gene test would show her child had only her DNA, and the child would invariably be female. But seeing as it also has not been observed in any other mammal, and there is strong biomolecular reasons to believe it cannot happen in mammals - it would be an extraordinary find, and would raise well deserved scepticism if claimed. If somebody claimed it and agreed to a DNA test though - then it would be confirmed.

  • Prior art in humans.

  • Now there's a redneck sport if there ever was one. I bet there are ATVs involved and everything. ;)

  • So she was in an aquarium alone and separated from her "long-term mate". Sounds pretty evil to me. These places need to be closed down.
  • Did they name the baby sharks Jesus II, Jesus III and Jesus IV?

    • Re: (Score:2)

      by dcw3 ( 649211 )

      I was about to post something like this, but I'm glad you'll be serving more time in hell instead of me now. Bravo!

    • Did they name the baby sharks Jesus II, Jesus III and Jesus IV?

      After the babies bit them.

  • Because it is so dangerous for a man to get married and have children due to unfair family law. MGTOW. Look it up

    • Re:Human females are going to have to do the same (Score:4, Interesting)

      by Ol Olsoc ( 1175323 ) on Thursday January 19, 2017 @09:28AM (#53695893)

      Because it is so dangerous for a man to get married and have children due to unfair family law. MGTOW. Look it up

      While MGTOW is a little interesting, way too much of it is butthurt whining. But the point is taken that an increasing number of men who would make good mates for a woman have done a risk/benefit analysis, and decided that it is not worth it.

      And that is kind of a problem. It's a passive avoidance, it isn't illegal. It's like avoiding smoking by not smoking. And as VR and "sex dolls" become more realistic, will only become worse.

      What is worse, while stable prudent men decide to pursue their careers and keep their assets, and avoid relationships with females, the jerks and abusers won't change at all.

  • From the summary: "Intrigued, Christine Dudgeon at the University of Queensland in Brisbane, Australia, and her colleagues began fishing for answers."

    "Fishing", got it?

    No?

    Sharks are fishes, you know?

    If needed I can be more explicit, just ask.

  • Good news! (Score:3)

    by Ol Olsoc ( 1175323 ) on Thursday January 19, 2017 @09:13AM (#53695809)
    For human women. After parthenogenesis is perfected, Human males will become useless parasites, and can finally be eliminated, ending all of the problems on earth.
    • Then the women would die off because as a group they consume way more resources than they produce. Men produce more resources than they consume overall.

      • Then the women would die off because as a group they consume way more resources than they produce. Men produce more resources than they consume overall.

        Tha's not what she said!

  • i have been telling this to my wife, as she always got pregnant when she was travelling and i was not around. i think missing me caused her to learn how to becomes pregnant by herself.

  • So the baby is a clone of the mother?

    • Re:Clone (Score:4, Informative)

      by ImprovOmega ( 744717 ) on Thursday January 19, 2017 @11:48AM (#53696827)
      No. It would be more like if you combined the genetic material of two eggs from the same mother together. It's a mish-mash of genes with a high degree of of similarity. So for example your odds of getting two copies of the same gene are greatly increased. This leads to a higher degree of birth defects and recessive gene combining in unpleasant ways. A clone would actually be *less* genetically damaged.

      That being said, it probably works out more-or-less okay for one generation but much beyond that it quickly becomes unsustainable.

  • The scientists will have to speak on her behalf, on Maury, Springer, and Wilco.

    He's the father!

  • At the aquarium, a little kid was heard shouting "go fuck yourself" to the shark tank a few months ago.
  • It's every woman's dream to be rid of the need for men!
  • The real question is how come, after 13 years, they decided to separate what was evidently a very successful pair of sharks? Seems that it would be wise to just keep them together.

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