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Fruit fly parasite's gene invasion raises questions over evolution
by Alok Jha
Reposted from:
http://www.guardian.co.uk/science/2007/aug/31/4
Scientists have found the genes of an organism fused wholesale into the genome of an entirely separate species, raising new questions over how evolution works. The discovery suggests that simple bacteria and animals might swap entire genes more often than previously thought. Such large-scale transfer of genes would allow species to acquire entirely new functions and abilities in a very short space of time, rather than the much slower sequence of random mutations that normally evolves species over several generations.
Jack Werren, a biologist at the University of Rochester, led a team to studying fruit flies infected with Wolbachia, a parasitic bacterium which invades 70% of the world's invertebrates and has developed a symbiotic relationship with many, co-evolving with them. Once Wolbachia invades a member of a species, it eventually makes its way into the host's eggs or sperm, ensuring it is passed on to the next generation of fruit flies. "The parasite's entire or nearly entire genome has been absorbed and integrated into the host's. The host's genes actually hold the coding information for a completely separate species," said Prof Werren.
Jonathan Sherwood, of the University of Rochester, said the discovery might have implications for gene-sequencing projects around the world, which normally discard bacterial genes from their samples, tagging them as contaminants. It might also shed light on human evolution.
For more information on this topic, go to:
http://www.physorg.com/news107702428.html
http://www.guardian.co.uk/science/2007/aug/31/4
Scientists have found the genes of an organism fused wholesale into the genome of an entirely separate species, raising new questions over how evolution works. The discovery suggests that simple bacteria and animals might swap entire genes more often than previously thought. Such large-scale transfer of genes would allow species to acquire entirely new functions and abilities in a very short space of time, rather than the much slower sequence of random mutations that normally evolves species over several generations.
Jack Werren, a biologist at the University of Rochester, led a team to studying fruit flies infected with Wolbachia, a parasitic bacterium which invades 70% of the world's invertebrates and has developed a symbiotic relationship with many, co-evolving with them. Once Wolbachia invades a member of a species, it eventually makes its way into the host's eggs or sperm, ensuring it is passed on to the next generation of fruit flies. "The parasite's entire or nearly entire genome has been absorbed and integrated into the host's. The host's genes actually hold the coding information for a completely separate species," said Prof Werren.
Jonathan Sherwood, of the University of Rochester, said the discovery might have implications for gene-sequencing projects around the world, which normally discard bacterial genes from their samples, tagging them as contaminants. It might also shed light on human evolution.
For more information on this topic, go to:
http://www.physorg.com/news107702428.html
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Posted: Friday, August 31, 2007 | PermalinkComments 1 - 25 of 25 |
Reload Comments | Back to Top | Page Numbers2. Comment #66750 by kelphis on August 31, 2007 at 7:59 am
you all know what this means? the creationist loons will jump on this to show how wrong evolution is.Other Comments by kelphis
3. Comment #66755 by kraut on August 31, 2007 at 8:13 am
Just another daft newspaper writer who cannot distinguish between evolution and mutation.BTW - the bacteria as god? I don't think the creationist want to touch that one.
Other Comments by kraut
4. Comment #66759 by Northern Bright on August 31, 2007 at 8:37 am
"Raising new questions over how evolution works" is not quite the same as "raises questions over evolution", as I'm sure the Guardian science editor is perfectly aware. 2. Comment #66750 by kelphis on August 31, 2007 at 7:59 am
you all know what this means? the creationist loons will jump on this to show how wrong evolution is.
Sigh. They certainly will (since they always do). Though I think they'll struggle to claim that Creationism accounts for this phenomenon any better! :-)
Other Comments by Northern Bright
5. Comment #66764 by catalinmerfu on August 31, 2007 at 8:49 am
RD is describing the process in TSG.How come this is new?
Other Comments by catalinmerfu
6. Comment #66772 by idragosani on August 31, 2007 at 9:49 am
Geez, you think these journalists can stop with the sensationalist headlines? What would have been wrong with something like "Fruit fly parasite's gene invasion provides more insight into evolution"? The "raises question" bit leads people to think "raises doubts". Other Comments by idragosani
7. Comment #66775 by the izz on August 31, 2007 at 10:04 am
It is so frustrating when a newspaper takes a story that actually could strengthen the case for evolution in the minds of the public and slaps a headline on it that makes it seem as though the enter theory were in jeopardy. I think most people (I'm paraphrasing my mother and sister's objections here) find evolution and natural selection hard to believe because they can't see that truly tiny changes have enough time to accumulate into large changes. They understandably can't get their minds around the vast lengths of time evolutions has to work with. So any discovery that gives an explanation for why change can happen faster than previously though tends to make the theory seem more plausible to the less science literate among us. Other Comments by the izz
8. Comment #66776 by mdowe on August 31, 2007 at 10:12 am
We've known about things like transposons and endogenous viruses for some time now. I don't see why this "gene invasion" would come as a particularly big surprise. Other Comments by mdowe
9. Comment #66780 by riemann on August 31, 2007 at 11:19 am
mdowe, i believe it comes as a suprise because although it is apparently yet another one of those rare exceptions to the weismann barrier (otherwise known as the continuity of germ-plasm), this particular exception occurs in a process that is rather common in nature, and therefore might have further implications about the course of evolution (not quite sure what they might be though). Would love to hear some expert comments.Other Comments by riemann
10. Comment #66783 by Pentecost on August 31, 2007 at 11:47 am
mdowe,There are very few (known) examples of prokaryote (bacterial) genes becoming incorporated into a eukaryotic geome. This is a very exciting find for bacteriologists, at least.
-P
Other Comments by Pentecost
11. Comment #66784 by glittergulch on August 31, 2007 at 11:50 am
In the Selfish Gene Dr. Dawkins talked about the idea that if two species work together intimately enough in a sort of positive parasite kind of way (i.e. work towards the same goals) they might eventually cease to really be two separate species. I think he pointed out how the internal organs of a complex creature all have their own jobs but work towards a similar end goal.I read that at the time and thought "that's neat but how the hell could two creatures go from being separate to being one? Well, here's a concrete example. Wow.
Other Comments by glittergulch
12. Comment #66788 by Russell's Teapot on August 31, 2007 at 12:15 pm
you all know what this means? the creationist loons will jump on this to show how wrong evolution is.
It wouldn't be surprising, since they seem to have the dubious talent of spinning similar scientific findings to "support" creationism, no matter how fuzzy the logic.
Other Comments by Russell's Teapot
13. Comment #66789 by Russell's Teapot on August 31, 2007 at 12:16 pm
Sorry for the double post, but how the heck do you get an avatar on these article comments? Other Comments by Russell's Teapot
14. Comment #66793 by Corylus on August 31, 2007 at 12:33 pm
Russell's Teapot Took me ages to work this out myself. I recently wrote detailed instructions for someone else, I reproduce below:
1) When logged in look at one of your comments. Click on your name.
2) You will be taken onto a blue page with 'Viewing Profile' on it. At the top left hand side you will see 'Board Index' written. Directly below this you will see 'user control panel'. Click on this.
3) On the 'user control panel' page - which is laid out like a card index - you will see a tab with 'profile' on it. Click on this.
4) You will now see a page asking you to 'edit profile'. On the left hand side you will see the option 'edit avatar'. Click on this.
5) On the 'edit avatar' page in the middle is an option to 'upload from your machine' with 'browse' on the side of it.
6) Click on 'browse' you will then be able to download/upload (buggered if I know the difference) a presaved picture from your PC's memory.
7) Make sure your file is not too big (the maximum dimensions are given on the page).
N.B. You might want to check the properties of any picture before you try to download - you may have to crop or compress accordingly.
Other Comments by Corylus
15. Comment #66807 by sabre_truth on August 31, 2007 at 2:25 pm
I agree that the headline is phrased in a potentially misleading way. I don't know whether that is intentional or just a case of sloppy language.This would be further evidence of "gene transfer" and a suggestion that it occurs much more frequently than previously assumed. It strengthens the case for the influence of mechanisms other than mutation in the evolution of species' genomes. These mechanisms offer potential shortcuts in the tedious process of accumulating adaptive mutations.
I think it should be definitely greeted as a reason for people to believe in naturalistic evolution who don't already, because it should make it more believable that there has indeed been enough time in Earth's history for the diversity and complexity of organisms to develop without any outside intervention.
Many evolution doubters display not only an ignorance of the evidence outside of the fossil record, but also of the discoveries of these novel mechanisms which indicate that we don't have to just sit around and wait for adaptive mutations to accumulate. Evolution has had a lot of help from ecology.
Other Comments by sabre_truth
16. Comment #66820 by Russell's Teapot on August 31, 2007 at 4:32 pm
Thank you for the help, Corylus :) Is there any reason why it would allow me to upload the avatar, but not display it on my comments? I've confirmed that the darned thing shows up in forum posts, but my poor name is image-less in article comments still.I even made sure it was 109x96 pixels and 15 kB...Do you need a certain amount of posts?
Other Comments by Russell's Teapot
17. Comment #66868 by eric.malitz on August 31, 2007 at 10:01 pm
'darwin's blind spot' is a good book on this stuff (co-evolution, and inter-species genes). however, ignore his swipes at dawkins' selfish gene; he apparantly hasn't read it or read it so long ago he forgot that dawkins himself described this process pretty similarly.Other Comments by eric.malitz
18. Comment #66878 by DNAtheist on August 31, 2007 at 11:18 pm
Kelphis wrote:you all know what this means? the creationist loons will jump on this to show how wrong evolution is.
Northern Bright wrote:
Sigh. They certainly will (since they always do). Though I think they'll struggle to claim that Creationism accounts for this phenomenon any better! :-)
You are right about that. This pretty much demolishes their concept of divinely created "kinds" which are forever separate. Unless, of course, bacteria and fruit flies are the same "kind."
Other Comments by DNAtheist
19. Comment #66914 by Corylus on September 1, 2007 at 1:43 am
Beat's me Russell's Teapot - I'd email admin if I were you. Other Comments by Corylus
20. Comment #66996 by robotaholic on September 1, 2007 at 9:20 am
sure that article is scientific and neeto but gosh, its' gross - "a parasite that infests egg and sperm of fruit fly" ARGHHHHHH Other Comments by robotaholic
21. Comment #67017 by bluebird on September 1, 2007 at 10:50 am
robotaholic,Aye, I "second that emotion".
http://www.physorg.com looks interesting...
Other Comments by bluebird
22. Comment #67134 by GodlessHeathen on September 2, 2007 at 5:11 am
I do so love when new facts come along forcing revision (or even abandonment) of theories. There is no more certain an indicator that our body of knowledge has broadened.And the more we know, the better equipped we are to make our lives better, expanding everyone's chances at capturing a little happiness. It gives me the nicest case of warm fuzzies.
Reason grants me more of that hope and good feeling than any religion I ever tried.
I'm a happy li'l' atheist.
Other Comments by GodlessHeathen
23. Comment #67135 by Richard Morgan on September 2, 2007 at 5:28 am
"Gene invasion"? I told they were nasty fascist things.How did they get through security? Other Comments by Richard Morgan
24. Comment #67209 by Goldy on September 2, 2007 at 4:47 pm
Sounds almost mitochondrial in action...Other Comments by Goldy
25. Comment #69214 by Xavier on September 10, 2007 at 2:56 am
Here is a link to University of Rochesters press release.http://www.rochester.edu/news/show.php?id=2963
It says the same as the Physorg link above. However, linked to it is another article which is even more relevant to evolution.
Title:Parasite's Sperm-Encryption Scheme Keeps Species Apart
http://www.rochester.edu/news/show.php?id=174
The article describes the way in which the wolbachia bacteria directly affects the passing of its hosts genes into the next generation by stopping the development of an embryo created with an uninfected partner. This promotes speciation by a mechanism other than evolution (though evolution remains a vital part of the system - otherwise the raw fact of speciation would have no consequences in the long term)
Even more interesting is the definition of a species; if the whole wolbachia genome is being reproduced both on its own and within and by the hosts owns reproductive system, the parasite genes must have evolved some synergistic phenotype. Thus the parasite genome is evolving in the direction of the fitness of the host. Does that mean the parasite and host are in some sense the same 'replication vehicle', part of the same individual?
Perhaps the synergistic effect of the integrated genome is precisely that it blocks other wolbachia strains from infecting the host. The link between the integrated genome and the external, free-living one is immediately broken when their evolutionary imperatives become different. The host, with its new-look genome and predilection for others of its own kind becomes an instant new species.
Other Comments by Xavier
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1. Comment #66747 by Arcturus on August 31, 2007 at 7:56 am
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