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Baffling genetic barrier in some closely related species prevents interbreding

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  • Baffling genetic barrier in some closely related species prevents interbreding

    Source: http://www.scientificamerican.com/article/baffling-genetic-barrier-prevents-similar-animals-from-interbreeding/?&WT.mc_id=SA_DD_20140822

    . . . two species of birds — carrion crows, which predominate in western Germany, and the closely related hooded crows that prevail further to the east, in Sweden and Poland. The two groups can mate with each other, but they look very different — carrion crows are black, and hooded crows have black-and-gray bodies — and the birds strongly prefer mates of their own kind. For a long as anyone can remember, the two groups have remained distinct, save for a narrow band of habitat stretching from Denmark through eastern Germany to northern Italy where they sometimes intermingle.

    The crows present a puzzling question to biologists, which gets to the heart of what it means to be a species: Given that hooded and carrion crows can mate and swap genes, how do the two groups maintain their individual identities? It’s as if you mixed red and yellow paint in a bucket but the two colors stubbornly refused to make orange.

    In new research published in June in the journal Science, Wolf’s team has found that a surprisingly small chunk of DNA may hold the answer. A comparison of the carrion and hooded-crow genomes showed that the sequences are almost identical. Differences in just 82 DNA letters, out of a total of about 1.2 billion, appear to separate the two groups.

    Almost all of them are clustered in a small part of one chromosome. “Maybe just a few genes make a species what they are,” said Chris Jiggins, a biologist at the University of Cambridge in England, who was not involved in the study. “Maybe the rest of genome can flow, so species are much more fluid than we imagined before.”

    The findings are striking because they suggest that just a few genes can keep two populations apart. Something within that segment of DNA stops black crows from mating with gray ones and vice versa, creating a tenuous mating barrier that could represent one of the earliest steps in the formation of new species. “They look very different and prefer to mate with their own kind, and all of that must be controlled by these narrow regions,” Jiggins said.

    Crows aren’t alone in their behavior. A deluge of genetic data in recent years suggests that interbreeding between species is more widespread than scientists ever imagined. “I think people will be surprised and the view of species will be challenged as more data comes along,” Jiggins said. “I think it will lead to a fundamental shift in how they view what a species is.”

    © Copyright Original Source

    Glendower: I can call spirits from the vasty deep.
    Hotspur: Why, so can I, or so can any man;
    But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

    go with the flow the river knows . . .

    Frank

    I do not know, therefore everything is in pencil.

  • #2
    So, Jorge was right all along.

    Capital "E" Evolution is pure evil metaphysics.

    I shouda listened to him,

    K54

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    • #3
      I've heard of these before. IIRC they do interbreed, but the crossbreeds are weaker than either true breed. Thus there's selection pressure against interbreeding. What you've quoted suggests that being heterozygous for that DNA segment is bad news. Though if there's so little difference between the birds, I can't see how there can be much that would provide any breeding preference, so maybe there isn't any substantial barrier yet, it's just that the downside of doing so keeps the populations pure.

      Roy
      Jorge: Functional Complex Information is INFORMATION that is complex and functional.

      mikewhitney: What if the speed of light changed when light is passing through water? ... I have 3 semesters of college Physics.

      Mountain Man: First of all, the Bible is a fixed document.
      Mountain Man: … this is how liberals argue these days, with labels instead of ideas.

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      • #4
        The differences in colouration might play a part. Or maybe they don't like each others songs.
        sigpic1 Cor 15:34 εκνηψατε δικαιως και μη αμαρτανετε αγνωσιαν γαρ θεου τινες εχουσιν προς εντροπην υμιν λεγω

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        • #5
          One implication of this is, it could require amazingly small changes to trigger a speciation branching event. Something that causes slightly different coloration, pheromones, mating displays, etc.

          Comment


          • #6


            Subscribing so I can reread this later. I don't get it yet.

            "He is no fool who gives what he cannot keep to gain that which he cannot lose." - Jim Elliot


            "Forgiveness is the way of love." Gary Chapman

            My Personal Blog

            My Novella blog (Current Novella Begins on 7/25/14)

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            • #7
              Originally posted by shunyadragon View Post
              Source: http://www.scientificamerican.com/article/baffling-genetic-barrier-prevents-similar-animals-from-interbreeding/?&WT.mc_id=SA_DD_20140822

              . . . two species of birds — carrion crows, which predominate in western Germany, and the closely related hooded crows that prevail further to the east, in Sweden and Poland. The two groups can mate with each other, but they look very different — carrion crows are black, and hooded crows have black-and-gray bodies — and the birds strongly prefer mates of their own kind. For a long as anyone can remember, the two groups have remained distinct, save for a narrow band of habitat stretching from Denmark through eastern Germany to northern Italy where they sometimes intermingle.

              The crows present a puzzling question to biologists, which gets to the heart of what it means to be a species: Given that hooded and carrion crows can mate and swap genes, how do the two groups maintain their individual identities? It’s as if you mixed red and yellow paint in a bucket but the two colors stubbornly refused to make orange.

              In new research published in June in the journal Science, Wolf’s team has found that a surprisingly small chunk of DNA may hold the answer. A comparison of the carrion and hooded-crow genomes showed that the sequences are almost identical. Differences in just 82 DNA letters, out of a total of about 1.2 billion, appear to separate the two groups.

              Almost all of them are clustered in a small part of one chromosome. “Maybe just a few genes make a species what they are,” said Chris Jiggins, a biologist at the University of Cambridge in England, who was not involved in the study. “Maybe the rest of genome can flow, so species are much more fluid than we imagined before.”

              The findings are striking because they suggest that just a few genes can keep two populations apart. Something within that segment of DNA stops black crows from mating with gray ones and vice versa, creating a tenuous mating barrier that could represent one of the earliest steps in the formation of new species. “They look very different and prefer to mate with their own kind, and all of that must be controlled by these narrow regions,” Jiggins said.

              Crows aren’t alone in their behavior. A deluge of genetic data in recent years suggests that interbreeding between species is more widespread than scientists ever imagined. “I think people will be surprised and the view of species will be challenged as more data comes along,” Jiggins said. “I think it will lead to a fundamental shift in how they view what a species is.”

              © Copyright Original Source

              "As for my people, children are their oppressors, and women rule over them. O my people, they which lead thee cause thee to err, and destroy the way of thy paths." Isaiah 3:12

              There is no such thing as innocence, only degrees of guilt.

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              • #8
                Not totally new. I read something like this before concerning tropical birds, and the relationship between varieties, subspecies and closely related species, but was only observations in the wild and certain closely related groups did not appear to interbred.
                Last edited by shunyadragon; 08-25-2014, 07:07 PM.
                Glendower: I can call spirits from the vasty deep.
                Hotspur: Why, so can I, or so can any man;
                But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

                go with the flow the river knows . . .

                Frank

                I do not know, therefore everything is in pencil.

                Comment


                • #9
                  Found one of the references, but the text or published paper:

                  2012 J. Dylan Maddox, “Inbreeding avoidance, genetic neighborhoods, and gene flow in a tropical bird with limited dispersal" Florida Museum of Natural History.

                  Still looking . . .
                  Glendower: I can call spirits from the vasty deep.
                  Hotspur: Why, so can I, or so can any man;
                  But will they come when you do call for them? Shakespeare’s Henry IV, Part 1, Act III:

                  go with the flow the river knows . . .

                  Frank

                  I do not know, therefore everything is in pencil.

                  Comment


                  • #10
                    Originally posted by klaus54 View Post
                    So, Jorge was right all along.

                    Capital "E" Evolution is pure evil metaphysics.

                    I shouda listened to him,

                    K54
                    Why doesn't metaphysics ever come in amoral or morally ambiguous flavouring anymore?
                    "When the Western world accepted Christianity, Caesar conquered; and the received text of Western theology was edited by his lawyers…. The brief Galilean vision of humility flickered throughout the ages, uncertainly…. But the deeper idolatry, of the fashioning of God in the image of the Egyptian, Persian, and Roman imperial rulers, was retained. The Church gave unto God the attributes which belonged exclusively to Caesar."

                    — Alfred North Whitehead

                    Comment


                    • #11
                      Originally posted by Duragizer View Post
                      Why doesn't metaphysics ever come in amoral or morally ambiguous flavouring anymore?

                      "S" for "STOOPID"!!!

                      Yayyyyyyy !!!!!!! He's back !!!!!!!!!! Mr "S" himself !!!!!!!!! He was missed!

                      Jorge

                      Comment


                      • #12
                        Dur!

                        "He is no fool who gives what he cannot keep to gain that which he cannot lose." - Jim Elliot


                        "Forgiveness is the way of love." Gary Chapman

                        My Personal Blog

                        My Novella blog (Current Novella Begins on 7/25/14)

                        Comment


                        • #13
                          Originally posted by Jorge View Post
                          Yayyyyyyy !!!!!!! He's back !!!!!!!!!! Mr "S" himself !!!!!!!!! He was missed!

                          Jorge
                          Just remember: embracing the absurd is a means to an end, not the end itself.
                          "When the Western world accepted Christianity, Caesar conquered; and the received text of Western theology was edited by his lawyers…. The brief Galilean vision of humility flickered throughout the ages, uncertainly…. But the deeper idolatry, of the fashioning of God in the image of the Egyptian, Persian, and Roman imperial rulers, was retained. The Church gave unto God the attributes which belonged exclusively to Caesar."

                          — Alfred North Whitehead

                          Comment


                          • #14
                            What might embracing the absurd lead to?
                            The greater number of laws . . . , the more thieves . . . there will be. ---- Lao-Tzu

                            [T]he truth I’m after and the truth never harmed anyone. What harms us is to persist in self-deceit and ignorance -— Marcus Aurelius, Meditations

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                            • #15
                              Originally posted by phank View Post
                              One implication of this is, it could require amazingly small changes to trigger a speciation branching event. Something that causes slightly different coloration, pheromones, mating displays, etc.
                              if that's all it takes, it seems to me rapid speciation is more common than was previously thought.
                              To say that crony capitalism is not true/free market capitalism, is like saying a grand slam is not true baseball, or like saying scoring a touchdown is not true American football ...Stefan Mykhaylo D

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