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DNA Detectives Count Thousands of Fish Using a Glass of Water
vinces99 writes "A mere glass full of water from Monterey Bay Aquarium's 1.2 million-gallon Open Sea tank is all scientists really needed to identify the Pacific Bluefin tuna, dolphinfish and most of the other 13,000 fish swimming there. Researchers also discerned which of the species were most plentiful in the tank. Being able to determine the relative abundance of fish species in a body of water is the next step in possibly using modern DNA identification techniques to census fish in the open ocean, according to Ryan Kelly, University of Washington assistant professor of marine and environmental affairs, and lead author of a paper in the Jan. 15 issue of PLOS ONE. 'It might be unpleasant to think about when going for a swim in the ocean, but the water is a soup of cells shed by what lives there,' Kelly said. Fish shed cells from their skin, damaged tissues and as body wastes. 'Every one of those cells has DNA and if you have the right tools you can tell what species the cell came from. Now we're working to find the relative abundance of each species present,' he said."
Being able to determine the relative abundance of fish species in a body of water is the next step in possibly using modern DNA identification techniques to census fish in the open ocean
"the machine says that by far the pacific is full of a fish called...poly vinyl chloride. hm, that's a funny name."
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Is this the MPAA? Is this the RIAA? Is this the DMCA? I thought it was the USA!
all scientists really needed to identify the Pacific Bluefin tuna, dolphinfish and most of the other 13,000 fish swimming there
What about species no-one knows about?
Questions raise, answers kill. Raise questions to stay alive.
Fish do piss in the water.
As far as I can see, the next logical step for the technique as outlined in TFA is to take a glass of sewage from a city sewage treatment center and analyze for the % of the number of human beings with a particular type of disease (HIV, TB, Polio or whatever).
Muchas Gracias, Señor Edward Snowden !
Followed swiftly by fish taxation.
Requiem for the American Dream
What about species no-one knows about?
As with other "soup" DNA techniques those species that they do not have DNA information for (I'm using this term loosely) would simply be separated by their genetic differentiation between each other. This is one of the primary problems with identifying species with "Soup" because organisms can be the same distance apart genetically but some may be different species morphologically and others may be the same.
In a simplified example say you have organisms A, B and C. A and B are closest genetically, A and C are furthest away while B and C are the same distance away from each other. One would look at this and assume A, B and C are separate species. However you then observe in the wild that B and C are able to breed, perhaps B and C are one species while A is separate? This is one of many examples of how genetic information can mislead species information
Unfortunately speciation is complicated and often not linear which leaves a confusing genetic trail. Fortunately, data telling us the genetic variation of an area can still be very useful for many scientific questions. Not to mention the usefulness of being able to identify the presence/ absence of well known species.
Fine and dandy.
Now, let's take another case: you know species A, you know nothing about B and C. Thus you can tell "A was here" but... can you tell there are other (exactly) two that "were here" as well? Maybe they were only one, maybe more than two. How can you tell?
Welp, that's exactly the problem, that isn't to say there aren't other methods though. For example you could see how much genetic differentiation there is between known species in the area and make assumptions based on that. You could also use other types of DNA, mitochondrial DNA for example which may tell a different story.
Fact is, taxonomists are always fighting about which species is which, sometimes with fruition. DNA, while it is very useful in determining one species from another has added to the questions about what really defines a species and what differentiates one from the other. Even morphologically there has been debate as to whether the two specimens you are holding are one species or two. Take the Eclectus Parrot for an early example, the male is bright green whereas the female is red/purple, scientists thought them to be separate species until they actually saw them mating. Things can get even more confusing when species don't physically mate with each other (think pollen and plants) or when they mate between species. Hopefully this type of science will take us closer to the answer.
On the other hand, personally I like these kind of studies for other uses like saying "Hey! This spot has way more genetically different organisms, maybe it's more important to not pollute it"
,quote>Fish do piss in the water.
Well, if you think about it practically every bit of water on the planet has been pissed by an animal at one time or another or at least is commingled with water that has.
Two decades ago I worked in a small team of “fish counters” to earn something during my time at university. This team was from the local government’s department of environmental protection and headed by a biologist. We’d drive up to a river, pull out our portable generator, drop one pole in the water, and walk in the river with the other pole, stunning the fish between the poles (they don’t die electrocuted, they are just stunned for a little while). We’d fish them out with nets, place them in large buckets and bring them on land, where the biologist counted and classified them before returning them to the river. His reports were then mainly used to assess the damages after an environmental disaster.
Once we were called to a spot where an oil truck had ended up in a mountain river. While we approached the place we wondered how that could have happened - the road was straight, no obstacles, excellent road conditions. But when we arrived we understood: right before the spot where the truck had left the road was a huge billboard with an underwear ad, featuring a nice young lady in a thong and nothing else. The driver must have craned his neck until the truck touched down in the river.
Hmm...I stand corrected. It appears rum as well is flavored by the products of yeast.
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