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Biotech Science

Aphid's Color Comes From a Fungus Gene 132

Posted by kdawson
from the long-jump dept.
Iron Nose writes with an account from Byte Size Biology of horizontal gene transfer from a fungus to an insect. The author suspects that we will see lots more of this as we sequence more genomes. "The pea aphid is known for having two different colors, green and red, but until now it was not clear how the aphids got their color. Aphids feed on sap, and sap does not contain carotenoids, a common pigment synthesized by plants, fungi, and microbes, but not by animals. Carotenoids in the diet gives many animals, from insects to flamingos, their exterior color after they ingest it, but aphids do not seem to eat carotenoid-containing food. Nancy Moran and Tyler Jarvik from the University of Arizona looked at the recently sequenced genome of the pea aphid. They were surprised to find genes for synthesizing carotenoids; this is the first time carotenoid synthesizing genes have been found in animals. When the researchers looked for the most similar genes to the aphid carotenoid synthesizing genes, they found that they came from fungi, which means they somehow jumped between fungi and aphids, in a process known as horizontal gene transfer."
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Aphid's Color Comes From a Fungus Gene

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    • Re: (Score:1, Redundant)

      by mrmeval (662166)

      They state with authority the gene came from a fungi but they have not shown where they have observed this happening. The fact that the genes are identical does not mean they're of the same origin.

      • by Thanshin (1188877)

        The fact that the genes are identical does not mean they're of the same origin.

        I've got little knowledge on the topic but I'd guess it's a matter of numbers.

        The larger the identical combination, the more probable is their common origin.

      • Re: (Score:2, Informative)

        by masterwit (1800118) *

        Carotenoids are colored compounds produced by plants, fungi, and microorganisms and are required in the diet of most animals for oxidation control or light detection. Pea aphids display a red-green color polymorphism, which influences their susceptibility to natural enemies, and the carotenoid torulene occurs only in red individuals. Unexpectedly, we found that the aphid genome itself encodes multiple enzymes for carotenoid biosynthesis. Phylogenetic analyses show that these aphid genes are derived from fungal genes, which have been integrated into the genome and duplicated. Red individuals have a 30-kilobase region, encoding a single carotenoid desaturase that is absent from green individuals. A mutation causing an amino acid replacement in this desaturase results in loss of torulene and of red body color. Thus, aphids are animals that make their own carotenoids.

        That's the abstract from the in-text link, whatever a Phylogenetic analyses is...my guess:

        Phase 1: Found genes......Phase 2: ???......Phase 3: Science! (good point mrmeval)

        • Re: (Score:2, Informative)

          by Anonymous Coward

          Well, they can't publish their entire paper in the abstract - the details cost you money, unfortunately. However, it's likely that the method they followed involved statistical comparisons of the nucleotide sequence for similarity. Initially, this seems to be pseudo-scientific, but there are a number of factors to consider: Eukaryotes(animals and fungi + others) make several modifications to the "raw" sequence before translation machinery can code protein from an mRNA template(exons, for example: http://en.

      • Re: (Score:2, Informative)

        by Anonymous Coward

        ...they have not shown where they have observed this happening.

        It's like paternity tests: you can't exactly get in a time machine and go observe it happening but when you calculate the probabilities based on reasonable assumptions they can come out pretty high.

      • Re:wiki (Score:4, Informative)

        by morty_vikka (1112597) on Monday May 03, 2010 @06:10AM (#32070444)

        The fact that the genes are identical does not mean they're of the same origin.

        Actually, if the genes are identical in terms of nucleotide sequence then it is absolutely irrefutable that they are of the same origin. Even genes that are evolutionarily conserved vary in sequence between members of the same genus, let alone organisms from completely different kingdoms of life.

        • The fact that the genes are identical does not mean they're of the same origin.

          Actually, if the genes are identical in terms of nucleotide sequence then it is absolutely irrefutable that they are of the same origin.

          It's indicative that they're the same, but not absolutely irrefutable. Any given sequence of DNA will be 25% identical to any other sequence, just because there are only four bases, while on the other end of the spectrum, even the DNA coding for something highly conserved, like cytochrome C, that exists in just about every eukaryote on the planet, isn't 100% identical across all eukaryotes.

          As such, if you have a gene that's only a couple dozen bases long, it's fairly likely that if you find exactly the sa

          • by Follis (702842)
            Your math is way off on the 25% figure. Any sequence with 4 letters in the alphabet and of length x will have probability 1/4^x of being identical to any other randomly chosen sequence of length x.
            • I didn't pay much attention in math class... but would you be willing to explain this a little more? It seems to me that if you have four letters, in a string, any two random strings you look at should have about 25% of their letters match between them. The chances that there will be any *sequences* that match drop as an exponential function of the number of letters in the matching sequence, right? but, for example, caggtcatgactaa and gattacagattaca, have a roughly 20% identical sequence, insofar as they
        • by swsbai (1585383)
          Impression births brought in big bad determine along one'study, body of http://www.watches21.com/ [slashdot.org]>replica watcheswork and animation.inward reality,impression dissembles not lone unmatchable heed only in addition to hullos body. Those with life-threatening low level impotent to keep their crop or carry extinct rule bodily function* of imprint. The symptoms mainly let in flavours from sorrowfulness, hopelessness, not wanting nutrient http://www.watches21.com/ [slashdot.org]>replica watchesand ail dormant.Besides, depr
  • by Anonymous Coward on Monday May 03, 2010 @05:11AM (#32070288)

    Well fuck me sideways.

  • I knew it! (Score:4, Informative)

    by masterwit (1800118) * on Monday May 03, 2010 @05:21AM (#32070320) Journal

    As an aside, many of our pseudogenes and other contents of “junk DNA” are thought to have been acquired by horizontal gene transfer.

    The guy behind the genetically mutated guido, look at his hand. (I'm sorry you cannot un-see that)

    On a more serious note, my roommate, a biology/pre-med major, found this article very interesting and said thanks.

    Apparently horizontal gene transfer (or at least inserting useless bits of DNA) is not very hard to do in a lab environment and is very common in bacteria, viruses, and other single celled organisms. Here is another link I found from 08 that talks about bacteria (E.coli) if anyone wants a read http://genomebiology.com/2008/9/1/R4 [genomebiology.com] (full text). Whatever I'm no expert in this field, but I like this type of stuff.

  • Movies (Score:3, Funny)

    by Thanshin (1188877) on Monday May 03, 2010 @05:29AM (#32070340)

    I wonder how soon I'll see this used in a movie.

    My bet is: Man becomes werewolf after eating many wolves.

    • I wonder how soon I'll see this used in a movie.

      District 9 [imdb.com]: African leader wants to eat a human mutating into an alien to gain his mutant-properties.
      The way this works isn't explained, yet it's implied it's a voodoo-belief.

      • No that's classic cannabalism. Eat your enemies to gain their power. See the movie Ravenous or wikipedia cannabalism.

        • Is this the very first instance of the noun wikipedia being used as a verb, or is it the very first time I have seen it?

          By the way, and movies aside, read The Ancestor's Tale by Richard Dawkins. It has a brilliant explanation of the various evolutionary genetic processes.

          • I've seen 'wiki it' a few times before.... And does Ancestor's tale go into detail about horizontal gene transfer methods? Or just touch on them?
          • by rcuhljr (1132713)
            First time you've seen it, you've heard of googling something I hope?
  • by CuteSteveJobs (1343851) on Monday May 03, 2010 @05:36AM (#32070356)

    According to this hottie (see link) black and brown are natural colors produced by pigments; usually red, oranges and yellows are the carotenoids which animals get from foods, and blues and greens (in birds) come from microstructure rather than actual color. (Obviously a green caterpillar gets the color from the diet. A bit different for animals, since I've never seen a green cow.)

    http://www.learnoutloud.com/Catalog/Science/Biology/Basics-of-Genetics/31316 [learnoutloud.com]

    She also says that horizontal gene transfer is very common, and that 90% of our DNA is viral. The viruses we hear about are the ones that make us sick. The ones that have no ill effects we don't notice so much; these are also called viruses or jumping genes.

    http://wheatoncollege.edu/quarterly/q2003fall/bacteria.html [wheatoncollege.edu]

    • by MichaelSmith (789609) on Monday May 03, 2010 @06:25AM (#32070482) Homepage Journal

      90% of our DNA is viral. The viruses we hear about are the ones that make us sick. The ones that have no ill effects we don't notice so much; these are also called viruses or jumping genes

      This is why I wonder about sexual behaviour which doesn't lead to reproduction. Could our genes have found ways to propagate themselves without reproduction?

      • It is only a matter of time before our genes make their way back to other species due to virus. Likely it will be short lived species that is in constant contact with us and mosquito's. I would suggest that Canine evolution is still on-going with dogs getting brighter and brighter possibly due to our genes being slowly transferred to them
        • by Xtravar (725372)

          I would suggest that Canine evolution is still on-going with dogs getting brighter and brighter possibly due to our genes being slowly transferred to them

          lol really? Domesticated dogs smarter than wolves?

        • by mutube (981006)

          In order for genetic material to persist it has to get into the germline cells - that is, sperm or egg - of the host. It's highly unlikely that 'just being around' humans would allow this to happen at all. Bacteria/fungal transfer is possible because, as an infecting pathogen, it can presumably get to where it is in close association with these germline cells - including, and probably limited to, the sexual orifices. So no, I seriously doubt dogs are getting smarter because they're picking up our genes.

          Sayi

          • So, you do not think that virus work their way back into germ cells? Hmmm. What exactly do you think feeds those? Do not think that blood is involved? Something new? And by what mechanism are virus blocked from entering germ cells?

            Now, if you have solutions for those (a different form of circulation other than bood and lymphatic that isolates the germ cells; and a means of blocking all virus from germ cells), then please share with the world, since you will win an INSTANT nobel prize.

            BTW, back in 77-81,
            • by mutube (981006)

              To be honest I missed the part in your post about the viral vector - I thought you were suggesting some direct gene transfer human-dog which was bizarre.

              It still seems a stretch to suggest that horizontal transfer from human to virus, then virus to dog could occur on anywhere the level required to produce an observable effect on canine intelligence. The vast majority of viruses are species-locked or species-limited and even if the virus can infect a host, the virus is further limited in which cells in the b

              • Hmmm. HIV? Swine and Avian Influenza? Swine and Avian comes to mind REAL quick. But that is simply because they cause a large amount of symptoms in multiple species. Likewise, HIV is certainly interesting to me, Personally. The reason is that I worked for CDC in 1980-81. I got to see ground zero of 'the homosexual disease' (and have to say that it played a major part in my switching careers to CS. 'The band played on' as well as the current written history, miss so many important thing from those early day
                • by mutube (981006)

                  HIV and influenza can cross species barriers - but neither infects dogs! They are also severely limited on which host cells they can infect and neither makes it into the germline. But, the point you make about asymptomatic viruses is an interesting one - the potential there is certainly underinvestigated - purely because of the large signpost screaming 'infection!' that usually gets the attention. The other side is interesting too - endemic infections that, aside from their obvious pathology, aren't investi

                  • The problem that we have is multi-fold. America used to be the PREMIER RD country. Sadly, reagan destroyed all that (what a crime). But that was followed by the drug companies realizing that they made more money by treating symptoms than the diseases. There is a good example of this: Psoriasis. Right now, drug companies are running around screaming that it is genetic (just like the ulcers). Yet, if you look at the incident rate, it is growing leaps and bounds inside of America. It is growing much faster t
    • by osgeek (239988)

      According to this hottie (see link)

      Yes, that static-like sound you hear is the cacophony of Slashdotters furiously mashing mouse buttons all over the planet.

    • by Judinous (1093945)
      I'm not sure that I buy that 90% number. The percentage of our DNA that is composed of endogenous retroviral material [wikipedia.org] is around 5-8% [nih.gov]. ERVs are horizontal gene transfers that occur in germ-line [wikipedia.org] cells, such as sperm, ova, and all of the cells in their ancestry back to the original zygote for that individual. Genetic changes to these cells (and only these cells) will be passed down to future generations.

      Now, it's true that ERVs are not the only type of viral DNA that an individual may have in their cells.
  • by Anonymous Coward

    Find something your precious "evolution" can't explain and suddenly it's "horizontal evolution"? Can't you see the facts as clear as day? This is the Intelligent Designer porting features from one creature to another!

  • Deadhead Aphids always like their fungus for the visual effect.

  • Just wait until... (Score:4, Insightful)

    by Errol backfiring (1280012) on Monday May 03, 2010 @06:39AM (#32070530) Journal
    Individuals are sued by Monsanto for being polluted by their patented genes.
  • Nature's own GMO (Score:3, Insightful)

    by mspohr (589790) on Monday May 03, 2010 @08:03AM (#32070914)
    This is an example of why I don't worry about man-made genetically modified organisms. It you have studied biology, you realize that nature is constantly shuffling DNA from one organism to another across species, genera, phyla and here across kingdoms.

    Nature is constantly performing billions of genetic engineering experiments, most of which don't work out. Sometimes there is a small evolutionary advantage. I don't worry about the "frankenfoods" taking over the world. Nature is constantly performing these experiments and the result is the the current highly optimized system we call "life on earth". Anything man creates just goes into the universal gene pool and has to compete with an already highly evolved system.

    • by biryokumaru (822262) <biryokumaru@gmail.com> on Monday May 03, 2010 @08:40AM (#32071096)

      To play devil's advocate here, a tiger represents millions of years of predatory evolution, yet we can still hunt it to extinction. Just because nature's been doing this a lot longer then we have doesn't mean its aims are the same as ours.

      When you're talking about evolution on the scale of millions of years, there's a selective pressure not to kill everything else around you. GE crops have no such incentive, and could quite possibly be extremely hard on the soil. Planting crops without regard to the needs of the soil is what led to the dust bowl.

      Of course, it's more than likely anything we create will be able to perform its intended function fairly well, but be utterly unable to cope with any other situation and quickly die out. I don't imagine we'd create anything highly adaptable, that's nature's thing.

      • by mspohr (589790)
        Large animals are relatively easy to hunt to extinction. (The disappearance of woolly mammoths and saber tooth tigers, among others, corresponds clearly with the "rise" of humans). However, genes are nearly impossible to get rid of... the genes of extinct animals live on in their relatives.

        I would argue that "selective pressure" is a competition designed to get rid of "less fit" genes, not to encourage them. However, as in the case of large animals, even "unfit" genes have a way of hanging around foreve

      • Re: (Score:3, Informative)

        by osgeek (239988)

        I don't imagine we'd create anything highly adaptable, that's nature's thing.

        Genetic tinkerers don't create anything in the "from scratch" sense. They copy complex and fully-formed genes from one life form to another.

        It's like using a well-debugged library in a new application.

      • by snowgirl (978879)

        To play devil's advocate here, a tiger represents millions of years of predatory evolution, yet we can still hunt it to extinction. Just because nature's been doing this a lot longer then we have doesn't mean its aims are the same as ours.

        When you're talking about evolution on the scale of millions of years, there's a selective pressure not to kill everything else around you. GE crops have no such incentive, and could quite possibly be extremely hard on the soil. Planting crops without regard to the needs of the soil is what led to the dust bowl.

        Of course, it's more than likely anything we create will be able to perform its intended function fairly well, but be utterly unable to cope with any other situation and quickly die out. I don't imagine we'd create anything highly adaptable, that's nature's thing.

        Like Corn/Maize... which can't propagate without human intervention. If we disappeared, the first generation of corn would overseed the soil, and each kernel would compete against all the others to grow, and result in each one starving out.

        We don't need GMO to make plants that are "utterly unable to cope with any other situation".

        • Like Corn/Maize... which can't propagate without human intervention.

          I've always felt that artificial selection should be considered genetic engineering. I don't know why it isn't.

          • by Urkki (668283)

            Like Corn/Maize... which can't propagate without human intervention.

            I've always felt that artificial selection should be considered genetic engineering. I don't know why it isn't.

            Because genetic engineering means manipulating the genes directly. Artificial selection doesn't do that, it let's the "normal" natural processes to do al the actual gene manipulation. I guess the borderline case is analyzing the DNA and performing artificial selection based on genotype. On the "traditional" side of that is artifical selection based on phenotype, and on the genetic engineering side is manipulating the genome directly (as opposed to let any DNA altering things happen in the "natural" way).

            Or

            • by snowgirl (978879)

              Civil engineers on occasion still dig trenches. (in German, I'd say "let a trench be dug," and it sounds fine, but in English it sounds like I'm being a pompous bitch.)

              Just because it's not the "high brow" version, or bleeding edge version, doesn't mean it doesn't qualify.

              Artificial selection is simply a tool of genetic engineering. And considering the differences between Maize and its closest cousin Teosintes; round-up ready crops are insignificantly different.

              • by Urkki (668283)

                Civil engineers on occasion still dig trenches. (in German, I'd say "let a trench be dug," and it sounds fine, but in English it sounds like I'm being a pompous bitch.)

                Just because it's not the "high brow" version, or bleeding edge version, doesn't mean it doesn't qualify.

                Artificial selection is simply a tool of genetic engineering. And considering the differences between Maize and its closest cousin Teosintes; round-up ready crops are insignificantly different.

                The results don't really matter, what matters is the methodology. Without the idea of genes and knowledge that genotype and phenotype are different, there can be no genetic engineering. Even with that knowledge, it won't be genetic engineering unless the knowledge is actively applied.

                So I'll give you that genetic engineering pre-dates discovery of DNA. In Europe I guess genetic engineering was first practised when Mendelian genetics was applied into practical breeding. But I bet most artificial selection (i

                • by snowgirl (978879)

                  While I understand that genotype and phenotype can be different, on a large statistical scale those phenotypical features that are governed by genotype become apparent, and can be selectively applied.

                  The idea that until we had Mendelian genetics we didn't practice "genetic engineering" in artificial selection is, in my opinion, a dim view; the same that purposes that people simply forgot that the Earth was round after the Greeks proved it.

                  They may not have understood the actual mechanism, but they still und

          • It isn't because there is a technical difference (randomly mixing thousands genes via controlled pollination vs. inserting one gene precisely) even if the end product is similar, indeed, I don't see how any GMO trait could not be achieved with sufficient time and breeding (although we might be talking on an evolutionary timescale here), but let's call a spade a spade, the reason so many people act like there's such a huge difference is mostly because genetic engineering is new and creepy and they don't unde

            • It isn't because there is a technical difference

              It IS because there is a technical difference.

            • by Urkki (668283)

              People act as if there is a rift between genetic engineering and breeding techniques. There's not, they're just different tools for different situations, and each have their uses.

              I'd say the difference is pretty much like the difference between traditional windmill and an atomic power plant. There certainly is a rift, one has vastly more potential to do damage to the environment. (Of course, if you take into account population growth and all that, relying on old "safe" methods, may indirectly end up doing more damage than using newer, potentially more dangerous but otherwise superior methods, but that's beside the point when assessing the direct damage potential.)

              The key thing with

              • by SEE (7681)

                Selective breeding techniques for plants used most of the last hundred years involve breaking up chromosomes with radiation to create new and completely untested genes, then taking any of the mutants that seem to have benefited from this and spreading their randomly-created genes far and wide throughout the species.

                Genetic engineering takes long-existing genes of known function and carefully inserts them into a species to create a predictable effect.

                And yet people who do the second are the ones who get port

                • by Urkki (668283)

                  Selective breeding techniques for plants used most of the last hundred years involve breaking up chromosomes with radiation to create new and completely untested genes, then taking any of the mutants that seem to have benefited from this and spreading their randomly-created genes far and wide throughout the species.

                  Genetic engineering takes long-existing genes of known function and carefully inserts them into a species to create a predictable effect.

                  The crucial difference can be read between the lines even in your text. Speed. Being able to engineer the genetic changes allows churning out new, functional genetic variations at far faster pace. I'd expect our capability to double per two years or so (as calculated in man-years to engineer a new genetic functionality, or amount of functional changes engineered per generation, or number of interacting genes possible to handle, or whatever is relevant to the field).

                  Also our ability to put these rapidly d

    • Re: (Score:3, Interesting)

      AMEN. As one planning on going into this area, I think about genetic engineering a lot, and that was the first thing that came to my mind too. I love how the anti-GE guys out there rail against the 'dangers' of foreign DNA being inserted into plants yet are blissfully unaware that species get foreign DNA all the time. Humans are 3-8% viral DNA depending on who you ask, and we're more genetically similar to chimps than two unrelated types of corn are to each other. My worry is that, in typical crank fashi

      • I love how the anti-GE guys out there rail against the 'dangers' of foreign DNA being inserted into plants yet are blissfully unaware that species get foreign DNA all the time.

        Yes. Perhaps with the little insicnificant difference that nature tests its "genetic engineering" thouroughly a couple of million years before releasing it to the public ...

        • You must be joking. Tell that to to people who are allergic to peanuts, or have celiac's and can't eat wheat, or had a drug interaction with a grapefruit, or died from eating a starfruit. Don't anthropomorphize nature. It doesn't care of how things turn out, it doesn't care if you have an anaphylactic reaction to kiwis or whatever, it just is. It just goes, and while it does so fantastically, it doesn't care what effects any given mutation will have. Giving it any traits beyond that is just magical thi

          • You must be joking.

            Sure, I'm joking. And while I was at it, I made up Superbugs [wikipedia.org] and Superweed [slashdot.org] as well. And let's not forget Monsanto's [wikipedia.org] activities [bangmfood.org] on that matter. A layman would think that if all's so good and well, a company like this wouldn't need all that lobbying and lawsuits.

      • I don't have a problem with us adding genes to plants. Hell, start adding genes to people! Put computer chips in someone else's brain first...then I'll jump in! Let the furries live their dreams!

        Where I have a problem is when Monsanto comes in after the fact and says "Well, well, well...awfully good looking crops ya have there. Be a shame is something were to happen to them. Like say our dominant gene with a kill switch enabled in it were to cross pollinate with your current crop....a reeeeaaaal shame. G
    • This is an example of why I don't worry about man-made genetically modified organisms. It you have studied biology, you realize that nature is constantly shuffling DNA from one organism to another across species, genera, phyla and here across kingdoms.

      And the above statement is precisely why I have begun to worry about genetically modified organisms.

      The whole concept of safety in GMO is defined in terms of species and genus, and that these abstract categories humans use to think about biology are somehow intrinsic in reality. That genes can migrate so easily across these categories shows this is not the case. Species, genus, phylum, and kingdom turn out to be convenient fictions, like centrifugal force. These fictions are an inadequate framework for wo

      • The whole concept of safety in GMO is defined in terms of species and genus

        Safety is assessed based on if it can be shown to cause health effects, even if it produces a new chemical that could cause those effects. The evidence to indicate that the vast majority of GMOs possess these health concerns is hugely underwhelming. I don't know where you get that taxonomy plays into it.

        We need a much better understanding of really basic biological principals to replace the rigid classification hierarchy with a way of thinking about the flows of information, materials, and energy that are an ecosystem. Until we have that more realistic framework and can use it to guide research and applications, I find the concept of using GMO in the field rather disturbing. At a very basic level, scientists and engineers involved in GMO research and applications don't know what the f*ck they are doing.

        And when will that be? What amount of knowledge will be sufficient to safely work with individual genes instead of mixing thousands of genes like we've been doing with selective breeding? Think about it,

        • Ack, forgot a part: Safety assessment for environmental damage- again, nothing hugely great to indicate that there's much worry there, although I have heard reports of cross pollination in wild populations of corn (by which I assume they mean corn relatives). Not sure just how prevalent it is or how accurate those reports were, but either way, the issue here isn't so much what harm they cause to the environment as the net harm. Farming is very bad for the environment, especially with our large population,

    • by Urkki (668283)

      This is an example of why I don't worry about man-made genetically modified organisms. It you have studied biology, you realize that nature is constantly shuffling DNA from one organism to another across species, genera, phyla and here across kingdoms.

      Nature is constantly performing billions of genetic engineering experiments, most of which don't work out. Sometimes there is a small evolutionary advantage. I don't worry about the "frankenfoods" taking over the world. Nature is constantly performing these experiments and the result is the the current highly optimized system we call "life on earth". Anything man creates just goes into the universal gene pool and has to compete with an already highly evolved system.

      Yes, but if this "natural experimentation" hits something extraordinary, it may be a disaster for the current ecosystem. It doesn't happen much in nature, in fact it's very rare on human time-scales. But when we start to do it, it suddenly happens much more frequently, and therefore also changes that may ravage ecosystems happen much more frequently. Also, in nature, every change is "out there", even if they actually do nothing. Humans purposefully design changes that do something, and only "working" change

  • There are a LOT more virus running around and we have very little appreciation for what they (and the lowly mosquito) do. Basically, as biologists continue to explore and some more get a bit of logic, they will realize that the vast majority of virus are asymptomatic (at least in a short term). Oddly, it will take time for ppl to accept the fact that virus do the majority of gene transfer (iow, it is not from mutation). Several interesting implications for this is that bio-diversity is conferred by bird/mo
  • Carotenoids in the diet gives many animals, from insects to flamingos, their exterior color after they ingest it

    Doesn't explain why WW2 night fighter pilots didn't turn orange.

  • Carrot Top!
  • ... in his Science Blog [scienceblogs.com].

  • Not so long ago, transposons (jumping genes) were thought to happen only in "lower" animals, not in humans. We now know that transposons are common in humans. They also said the same of copy number variations, or of DNA letters different from A/C/G/T.

    The current dogma of genetics says that DNA homology between species is caused solely by evolutionary relationships. How long before we realize that this isn't true either?

    I'm not an evolution denialist, but I do think the current scientific understanding of

    • I'm not an evolution denialist, but I do think the current scientific understanding of evolution has a religious zeal.

      The fact that this type of finding actually refutes most current hypotheses of evolution, yet people are attempting to use evolution to explain it, and the article is tagged "evolution", I would say that you made a bit of an understatement.

      • by Shipud (685171) *
        Actually, it does not refute anything. HGT has been known to exist for a long time in all of life's kingdoms, and has no impact on the Theory of Evolution. It is yet another genetic variety generating mechanism, on top of sex. The authors provide a very plausible mechanism to explain how the gene got fixed in the population. BTW, if you don't believe in evolution, how can you on the one hand accept their inference of HGT which is based on evolutionary considerations (sequence similarity and homology), but
        • Poor analogy. It's more like saying that cars clearly run off a combustion of air and gasoline, then finding out that 20% of cars can run underwater indefinitely. It doesn't compliment the hypothesis, it refutes it. If the "air/gas combustion" was a theory, it would be reduced back to the drawing board. It shows that there are deep, underlying complexities involved that your air/gas cumbustion theory was drawn independent from -- not just that "Cars will run on air/gas except for some that run on water
      • by Urkki (668283)

        The fact that this type of finding actually refutes most current hypotheses of evolution,

        Could you be more specific? Ie. which part of the theory of evolution does this refute?

        Or you want a more specific question, in the context of the Theory of Evolution, how is getting new genes by horizontal gene transfer different from getting new genes by mutation?

        It's more like horizontal gene transfer mechanisms save theory of evolution in the face of genes shared by different families. If eg. aphids and fungus had same gene, but horizontal gene transfer can be disproved, then it means that they got the

    • by JoshuaZ (1134087)

      The current dogma of genetics says that DNA homology between species is caused solely by evolutionary relationships. How long before we realize that this isn't true either? I'm not an evolution denialist, but I do think the current scientific understanding of evolution has a religious zeal.

      Frankly, I don't think you understand what you are talking about. The linked to article is an example where DNA homology isn't due to an "evolutionary relationship" (that is, recent common ancestry) but rather horizontal gene transfer. And this isn't the only example of this. We have many other examples of horizontal gene transfer by viruses for example. See http://en.wikipedia.org/wiki/Endogenous_retrovirus [wikipedia.org]. However, we do know that the vast majority of similarities in DNA are due to evolutionary relation

      • by dorpus (636554)

        "However, we do know that the vast majority of similarities in DNA are due to evolutionary relationships because the genetic sequences when one graphs them by how different they are from each other form a tree, exactly as evolution would expect."

        Actually, no. DNA homology has re-drawn the "evolution tree" considerably, as species that were thought to be related turned out not to be, while other "unrelated" species turned out to be related. After re-drawing the tree, scientists now say this "proves" that D

        • by JoshuaZ (1134087)
          That's simply not true. We've had a lot of redrawing of minor aspects. But the overall tree looks almost identical to it did 30 or 40 years ago. The great apes for example look about what they should look like. As do mammals as a whole. Most of the redrawing that has occurred has been when we have a handful of species and we were wrong about the precise order they broke off from each other. It shouldn't be surprising that morphological data isn't always perfectly interpreted. The sort of thing that would se
          • by dorpus (636554)

            30 to 40 years ago, the tree of evolution was missing an entire kingdom of archaea. When I took high school biology, they told us that archaea are "extremely rare bacteria" that only live in hot springs. We now know this is not true; archaea are ubiquitous, only scientists didn't know where to look. Biology teachers like to show microscope pictures as "proof" of whatever theory they teach, though it's interesting they spent hundreds of years unable to find archaea that live all over the place.

            We are no l

            • by JoshuaZ (1134087)
              I have to wonder if you're actually reading what you've linked to. There was a lot of controversy over where animals and sponges stood in relation to each other. That's discussed in the article in question. Genetic data settled that issue. The second one I'm very sure you didn't read at all since it is talking about a group of scientists arguing based on physical evidence that humans are more closely related to orangutans than chimps. They are making that argument despite the DNA evidence showing the revers
              • by dorpus (636554)

                Are chimps that similar to humans? Scientists have measured only mitochondrial DNA before to claim "99.9% similarity" between organisms, and that because this is DNA, it is indisputable truth. But then, if we apply the same standard to Y chromosomes, then chimps and humans are only about 50-66% similar, depending on the metric used.

                http://www.wi.mit.edu/news/archives/2010/dp_0113.html [mit.edu]

                And as MIT says, the chimpanzee is only the second Y chromosome to be comprehensively analyzed. Are you going to say for s

                • by JoshuaZ (1134087)
                  Dorpus, I really think it would help if you maybe brushed up on your level of biological knowledge. To be blunt, you seem to be repeatedly misunderstanding statements. In your post previous to this one, you completely confused what the article in question was saying about chimpanzees and orangutans and had other problems. Your recent comment above. Since I have finite amount of time, I'll only note four of them: First, you are confusing HIV with AIDS. What scientists would have said is that only primates co

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