New Science Of Metagenomics to Transform Modern Microbiology? 82
ScienceDaily has a look at the emerging field of metagenomics that watches the DNA of whole communities of microbes to better understand the microbial world. "Metagenomics studies begin by extracting DNA from all the microbes living in a particular environmental sample; there could be thousands or even millions of organisms in one sample. The extracted genetic material consists of millions of random fragments of DNA that can be cloned into a form capable of being maintained in laboratory bacteria. These bacteria are used to create a "library" that includes the genomes of all the microbes found in a habitat, the natural environment of the organisms. Although the genomes are fragmented, new DNA sequencing technology and more powerful computers are allowing scientists to begin making sense of these metagenomic jigsaw puzzles. They can examine gene sequences from thousands of previously unknown microorganisms, or induce the bacteria to express proteins that are screened for capabilities such as vitamin production or antibiotic resistance."
how do you... (Score:3, Insightful)
I always thought that DNA extraction was a manual process... or at least it required a significant amount of manpower to get.
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Which is, as I understand it (my wife does DNA extraction as part of her job) how DNA extraction is done, anyhow, whether its from a single multicellular organism or a mass of (normally, rel
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Gotta love curiosity. We really need an educational system that fosters curiosity and research above all else... it makes learning so much more fun.
Thanks for the reply!
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An excerpt from the Wikipedia article mentioned above:
"DNA is a molecule. Molecules are put together out of atoms, that have different charges; some positive some negative. The atoms it is made up of are A, T, G, C and sometimes U. All of the information from life is contained in the atoms of DNA. It is called the genetic code. The genetic code was invented by Watson and Crick. All information from life is passed down through generations by the process of meisosi. This is where the atoms line up and they
Curiosity (Score:2)
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If we could take a kid, from the time that they ask 'why?' about everything, and keep them in that super-curious state all the way through college... we wouldn't need to teach them so much as assist them in teaching themselves. And best of all, they would remember and understand th
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In theory, this would sequence everyt
The article summary is poop... (Score:2)
...which is why you're still having trouble. The article is in fact about new developments that allow this sort of thing, which as your belief would indicate, has not been possible so far. Check out this paragraph from TFA.
"Although the genomes are fragmented, new DNA sequencing technology and more powerful computers are allowing scientists to begin making sense of these metagenomic jigsaw puzzles. They can examine gene sequences from thousands of previously unknown microorganisms, or induce the bacteria
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It's like trying to unders
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Trying to take a ton of very granular heterogenous data (structure) and trying to figure out the function (how the system "works" or what it "does," or the understanding of the system as a gestalt) gets harder the more data you pick up. This is the problem biologists face and most of the new techniques in bioinformatics are specifically geared to solving it.
As a
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Its just a matter of breaking down the cell membranes- which are essentially fatty acids with proteins in them, easily dissolved by detergents. Next, separating the DNA from the rest of the cytoplasm, by putting the extract in alcohol.
A more challenging aspect is preparing the extracted DNA for analysis; you have to clone and amplify the DNA in order to make a DNA library, that becomes more expens
The right hardware (Score:1)
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Re:how do you... (Score:5, Informative)
The best this can do is tell you what genes are present in abundance. Often you may also need primers for that gene so you have to guess a portion of it before you go looking for it. Thus one has some blind spots but these are no worse perhaps than the simple reality that one must always miss some of the low concentration genomes. The presumption is that higher concentration genomes are the most important. That's debatable. If a martian sampled our planet he'd conclude we are irrelevant, and probably that nothing but the top layer of sea water was relevant, given the profile of DNA concentration. Maybe he's right, but I think he'd be missing out on using this to explain a lot of phenomena on earth. How would this explain for example high rise building, deforestation, or changes in the atmosphere, let alone nuclear explosions. For those you might need to sequence us.
Another problem with this kind of analysis is that while it tells you what is there it does not tell you how the genes interact. For that you need to measure things under varying condittions where relative abundances shift. E.g. finding conditions where nominally the same populations exist--highly coupled envirnonments in equilibrium--where there are different stresses and opportunities. Perhaps the best example of this is depth profiles in sea water. However, obtaining enough degrees of freedom in the experimental conditions, so that one can correlate DNA presence patterns is rough. These self-simmmilar variations can be factored out only under assumptions that need to be justified. Typically Linear factors are assumed and that's almost certainly not true. It certainly would be false in any situation involving either negative feedback or saturation effects. getting enough sample points of entire meta genomes is thus the limit. It's pretty heroic to do even one. And of course one replicate is not enough since one can't distinguish noise from variations one is seeking. So it's all very hard.
Thus it's sort of a race which will prove more powerful. Reductive decomposition of a population one species at a time or a discovery based meta genomic analysis.
the simple answer is we need to do both. When it works reduction is far more conclusive about interactions. But there's likely some aspects of community life that dont reside in any one geneome but are traits that float around between different "owners". Likewise, most environments like ground soils have proven to be unculturable so one is sort of stuck with metagenomics or nothing.
Sample collection is the easy part. (Score:2)
Abundance of material doesn't pose a problem. Soil samples are so abundant in diverse microorganisms that its actually a problem later on. For water sampling it is quite straight-forward to use tangential flow filters to collect sufficient biomass by simply processing the appropriate volume of water.
Of the shotgun sequencing type,
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You cracked me up.
Metagnomes! (Score:2)
You use metagnomes. They're the same gnomes who carry out step 2. If they can figure out how to extract profit from underpants, they can figure out how to extract DNA from millions of microbes.
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Extracting DNA is very easy:
The next step, cloning, is also easy to automate:
Did work in bacteriology and DNA extract was easy (Score:2)
You'd be surprised.
Modern PCR kits have become so much robust that you can put almost anything at them, and they still manage to duplicate the exact piece of genes that you need, without much artifacts.
At the last lab where I worked we use to take bacterial colonies and shake them with microbeads and... and thats it.
We developed a fast, high throughput and dead-cheap methods for genotyping (ie.: puting into sub-families according to gene properties
Re:Did work in bacteriology and DNA extract was ea (Score:2)
Original Source Here (Score:1)
Genetic Modification Tracking (Score:2)
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Nor is metagenomics all that interesting in pure cultures, where you've got billions of bugs with almost identical genomes. It will be much more useful in an extre
Deep sea studies (Score:1)
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New paradigm (Score:3, Interesting)
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Speaking of that, it reminded me of something (Score:2)
Source (Score:4, Interesting)
Oh, and here's a brief (4-page summary) of the report [nas.edu].
Woulda been nice to have the source info in the summary...
Don't tell a Republican! (Score:2)
Don't tell any Republicans about this.
The prez is already concerned about the possibility, and I quote from a speech: "human-animal hybrids".
Related Resource (Score:2, Interesting)
A website hosting the data from the expediti
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There is a lot of exciting research opening up!
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To think that genomes are just the tip of the iceberg. There is a whole planet of nucleic acids, RNA, virus, and membrane-free that are exchanging information and evolving far faster than genomes. I have to surmise there is a whole internet of genetics floating around and we are in the first steps of interfacing with it.
An open question: What is the mass and energy expended on the various forms (genomic, RNA, virus, membrane-free, etc.) of nucleic acids in a biology? How
any biologists in the room..ermm...slashdot? (Score:2)
You know, pondering about evolution, there is only one thing I have difficulty understanding with evolutionism (which I am a strong proponent of). I don't know if you're a biologist or not, but if someone could give me a good explanation I would be glad.
In the case of social groups of insects, like bees and ants, you have different classes/groups of individual insects within one hive, some of which are highly specialised. I can't quite understand how th
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For instance, like me example:
"Say the ancestors of the current ants were more simple, less specialised. At a certain moment, in the DNA of a queen-egg, there occurs a mutation; this mutuation turns out to be beneficial - say, the worker-ant develops an enzym which is far more efficient in providing digestable nutrients from raw food, for instance. Now, that ant lives its life, then dies
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The problem with this is that it ignores that not all genes an organism has are necessarily expressed and that, particularly, the expression of genes may be triggered (or suppressed) by environmental conditions or by the presence or absence of
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1. a mutation happen randomly in sperm or egg.
2. a new queen is born from this mutated reproductive cell.
3. mutation is positive (e.g. the slave from this queen are more efficient)
4. the queen give birth to more new queen than one with less efficient slaves
Let's look at it in another way.
Infertile workers are like our cells. You can have one white cells which is resistant to HIV, but this mutation won't be passed to your offspring. But maybe one of your sper
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Anyway, you are just trying to be helpful, I suppose. People seem to be a bit on the wrong track whith what I'm a
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You are right the queen genome encodes all the genes, but in each individual only a specific set of genes are activated. Which set is activated depends on growth conditions (feeding, temperature,
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Anyway, people seem to be a bit on the wrong track whith what I'm asking (maybe I explained it wrongly). I'm quite aware of how the way evolution works, and the importance of genes, but I would like to know the specifics how a mutation is tran
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A queen doesn't do anything, essentially, but lie around and produce offspring. Whether any of the few (proportionately) of those offspring which are fertile have reproductive opportunities depends on the success of the colony, which depends on how effective the workers (etc.) are. Ergo, a queen that produces more
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all the mutations are in the genes of the queen, but none of it comes to expression in the phenology of the queen
This is more or less correct. I think what most of the folks here are getting hung up on is some slight miss conceptions and a bit of confusion over your slightly odd use of terminology.
Okay, A summary of a few points to (hopefully) clear up some of this confusion:
It is important to distinguish between somatic cell mutations and germ line mutations. Based on what you've said already, it se
Re:any biologists in the room..ermm...slashdot? (Score:4, Insightful)
You're lying. Seriously. Only creationists use phrases like "evolutionism" and "darwinistic evolution."
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Your lying. Seriously. Kenan Malik uses 'evolutionism', and one can hardly claim he's a creationist. As an atheist, it would be rather difficult for me to believe in ID.
Being not native english, I'm not sure what you're getting at; are you implying the terminology is wrong? When I check in an online english dictionary, I see:
evolutionism (v'-l'sh-nz'm, 'v-) Pronunciation Key
n.
1)A theory of biological evolution, especially
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Starting from the base, you and I are made of hundreds (understatement) of types of cells -- other than stem-cells, each cell-type is highly specialized. A variety of specialized cells work in concert to comprise each organ, but the organs by themselves are useless, and unable to sustain life... the org
Metagenomics of the ocean (Score:1)
Mega-fast sequencing is making it all possible. (Score:1)
Marketing aside, keep it in perspective. (Score:3, Informative)
I'm not sure whether the above post should be marked "astroturfing" but it sure reads a little too positive.
454's sequencing technology is a welcomed addition to existing technologies, but don't believe the hype, particularly when the person talking has stock options.
The analysis of genomic sequencing data (metagenomics or otherwise) is highly benefited by large contiguous pieces or ideally whole contiguous genomes. Related to this and more fundemental is the fact that the shorter the pieces of DNA spat
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Please tell me with a straight face that you think you would have thought up doing a thousand simultaneous PCR reactions in an oil emulsion on beads then sequencing off the beads us
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FiB Episode 011 - Ancient DNA: The Neanderthal Genome
(The Futures in Biotech podcast: http://www.twit.tv/fib11 [www.twit.tv]
Drs. Paabo and Jarvie talk about the Neanderthal Genome Sequencing Project...
Guests: Dr. Svente Paabo, Director of the Department of Genetics at the Max Planck Institute for Evolutionary Anthropology
Dr. Thomas Jarvie, Technical Application Manage at 454 Life Sciences
In this episode, Dr. Svante
Sad tendency (Score:3, Interesting)
I have been reading scientific literature for almost 25 years and the tendency is clear: the results of "computer experemints" (read, modeling) are trusted more and more without any experimental verification. The procentage of sequences in GenBank and Refseq which function is determined only by homology to existing proteins grows. That means we are guessing the function of new proteins by comparing them to the proteins which function we also guessed by comparing to earlier proteins, etc...
Number of protein folds is limited: 700, 1000, 30000, does not matter: it is limited, but it does not mean the functions are limited in the same way. How on earth are we going to find out the function of completely new protein that have not enough similarity to anything in the database? We cannot do it on computers.
And obviously we do not have resources to research experimentally 1.5M genes in Refseq. So instead of blindly pumping more and more raw data into our RAID arrays, we need to be more focused on researching the genes, proteins, pathways that have a direct impact on medicine. You know, "stuff that matters".
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As to whether in-silico lab work is feasible, they jury is out. It may be that computers will be most useful as a complement or augment to lab techniques. It's indisputable that
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In my own research, I have relied on databases to determine what particular protein family a newly purified peptide (from a crustacean) belonged to, or to design primers for certain enzymes.
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