Scientists have located an algal virus that attacks human DNA

http://www.newsweek.com/american-researchers-discover-stupidity-virus-283319

by johnloeber • 12 years ago

93 47 12 years ago

newsweek.com

shkkmo2• 12 years ago

That is absolutely terrifying. I don't want to know what applications the DOD comes up with once the vector is known...

bdamm• 12 years ago

Yeah, I will never again eat "Made in China" candy.

fchollet• 12 years ago

92 volunteers, 43.5% were infected -> exactly 40 volunteers were infected, and 52 weren't. Then they claim to have found that the infected sample performed "10% worse" on intelligence tests.

Intellectual performance follows a gaussian distribution. If you take two random samples, one of 40 people, and one of 52 people, and you average the IQs in each sample, the probability that you will find a deviation 10% or greater one way to another is over 50%... in this particular case, to compute the probability of the null hypothesis precisely we would need the exact result distribution on the tests they used, but in any case, take these results with a pinch of salt.

shkkmo2• 12 years ago

Very true. I wish the article had the statistics behind this claim:

"The team carried out further tests, in which they injected uninfected and infected green algae into the mouths of mice and put them through a series of lab tests. The results revealed that infected animals took 10% longer to find their way out of mazes and spent 20% less time exploring new objects than uninfected mice."

Which is the much stronger experimental manipulation.

rwhitman• 12 years ago

There's a comment below with the full text of the study: https://news.ycombinator.com/item?id=8608989

anigbrowl• 12 years ago

Furthermore 'ATCV-1 exposure in mice also resulted in the altered expression of genes within the hippocampus. These genes comprised pathways related to synaptic plasticity, learning, memory formation, and the immune response to viral exposure.'

http://www.pnas.org/content/111/45/16106.abstract

So it seems like they have opened up multiple avenues of scientific inquiry - this strikes me as a much stronger result than presented in the Newsweek article. Assuming for the sake of argument that their speculation is correct, it's a rather frightening thought that some ~40% of the population could be suffering a significant virally-induced cognitive impairment. Also, I wonder if elimination of this virus could result in an improvement in cognitive and immune function.

The economic and public health implications of this research are potentially quite significant.

stillsut• 12 years ago

I thought: E[IQ] = 100, SD[IQ] = 10 then SD (for n = 37) = (10 / sqrt(36)) =~ 2

So a 10 point deviation between groups is 5 sd's, p <.001 ?

tokenadult3• 12 years ago

The standard deviation of IQ scores is 15 by definition. (That is, raw scores on the item content of IQ test batteries are generally not reported at all, but rather what is reported for each test-taker is a standard score defined as performance at the norming population median level being an IQ of 100, and performance one standard deviation up from that being an IQ of 115, and so on. All mainstream individual IQ tests have been scored this way for just about all of my lifetime.)

P.S. I would take four standard deviations up or down (the IQ range of 40 to 160) as the outer limit of validated IQ scores, and indeed few modern IQ test batteries purport to report scores outside this range. See

https://en.wikipedia.org/wiki/IQ_classification

and the published reference books cited there for more background.

P.P.S. I should have mentioned when I first posted this comment that any IQ test has a standard error of measurement even if it is faultlessly administered and scored. Sometimes small-n studies like the study reported here have IQ score differences between two groups that are simply the result of the test errors showing a difference where no actual difference exists. IQ tests are often also very frequently administered incorrectly or scored incorrectly even if correctly administered, magnifying the size of the error band around the obtained score. For this study, I'm not sure if the human subjects tested were tested by test-givers who were "blind" to what group the test-takers were in, which could also be an issue.

TrainedMonkey2• 12 years ago

That is true, but we can't translate 10% longer time taken on performing some task into 10% less effective IQ.

leeber3• 12 years ago

Guys, we're programmers here not statisticians:

def test():

... n1 = numpy.average(numpy.random.normal(100,15,52))

... n2 = numpy.average(numpy.random.normal(100,15,40))

... return abs(n1-n2) / ((n1+n2)/2.0)

...

>> vals = [test() for i in xrange(0,1000)]
>> numOver10 = len([v for v in vals if v > .1])
>> numOver10

leeber3• 12 years ago

Where in the world did you learn stats from?

You would be correct if we were talking about a standard normal distribution with mean 0 and standard deviation 1. Very different.

In the case of mean 100 and standard deviation ~15 or so, the probability of two samples being at least 10% different is very small like under 1%.

Gravityloss• 12 years ago

If this is real and a cure can be developed, think about the huge free boost it gives to humanity in total since it might affect such a large amount of people. On the other hand, I'm skeptical. With such drastic effects, wouldn't the evolutionary pressure for the immune system to deal with it have been tremendous?

TeMPOraL• 12 years ago

Since it apparently doesn't affect sexual performance much, would it?

Also it might be the case that the infection vector is something relatively new to us, something not present in the ancestral environment, like the tap water idea of ChuckMcM - https://news.ycombinator.com/item?id=8608780.

AnimalMuppet• 12 years ago

If it lowers intelligence and/or increases response time, it could affect survival. It's not enough to be able to reproduce, you have to live long enough to do it. So, yes, it would be subject to selection pressure.

jobu• 12 years ago

This virus may also give us more clues at which parts of our DNA affect intelligence - something that has difficult to pin down: http://www.nature.com/news/smart-genes-prove-elusive-1.15858

GFK_of_xmaspast• 12 years ago

You could have said the same thing about hookworm, and yet: material reality.

tokenadult3• 12 years ago

This is a preliminary research study and may not be replicated. Things I would want to know, after a replication study is published, is what the effect size is across more than one animal model (both mice and rats should be tried, and different strains of inbred mice with known differences in cognitive performance on mouse cognitive tasks should definitely be tried). I would also want a broader survey of human patients from more different parts of the world to see how many human beings show the same clinical sign the authors report here. And I'd want some of the human surveys to include very young participants, to see if rates of purported infection increase as human beings age. Right now, if I were to bet on this, my bet is that this result doesn't even replicate. (That's a reasonably good bet, as only about 50 percent of all scientific first findings, even those that have been published in a peer-reviewed journal, ever do replicate.)

ChuckMcM2• 12 years ago

One of the interesting things about tap water is that it periodically suffers from algae 'blooms' (which is addressed by chlorine but the remnants of the algae persist. I've asked Dr Yolken for a copy of the paper and if they have checked that vector. Once again I find myself thinking I should get a DNA sequencer so that I could analyze my own tap water more quickly.

[1] Original paper -- http://www.pnas.org/content/111/45/16106.abstract

Blahah• 12 years ago

When the Oxford Nanopore MinION comes out of the early access trials, you will actually be able to do this for a cost of somewhere around $1000.

ChuckMcM2• 12 years ago

I am totally going to buy one of those when it becomes available.

kolev2• 12 years ago

Illumina already sells a $1,000-genome machine. By the way, what's happened with the ambitious SV-based Halcyon Molecular, which was supposed to deliver a $100-genome sequencer?

P.S. Halcyon has shut down 2 years ago [1].

[1] https://gigaom.com/2012/08/19/halcyon-molecular-quietly-shut...

gwern2• 12 years ago

Fulltext: https://pdf.yt/d/dr3uP9XOtT1BPimU / https://dl.dropboxusercontent.com/u/5317066/2014-yolken.pdf / http://libgen.org/scimag7/10.1073/pnas.1418895111.pdf

ak39• 12 years ago

Thanks for this!

Nowhere, so far that I have read, have the scientists used the word "stupidity" as has the originally linked Newsweek article.

It was completely unnecessary for Newsweek to dumb down the research this way. Firstly cognitive impairment is not the same as general understanding of "stupidity" - a pejorative. Many things account for what we would usually term stupid behaviour. Personality, stress, hormonal balance are good examples. Then again, cognitive impairment includes a myriad of brain function impairments including memory loss ... forgetting something is hardly considered "stupid".

The research is important, but the careless use of words by Newsweek doesn't do justice.

toufka• 12 years ago

If you know what you're looking for, you just need a couple of enzymes and one of these OpenPCRs [1].

[1]http://openpcr.org/

twic• 12 years ago

So they tested a bunch of people, and found that those of them who regularly eat algae are a little less intelligent. Well, yeah.

DanBC• 12 years ago

The Japanese regularly eat algae. Are they less intelligent?

jacquesm• 12 years ago

Sweetwater algae vs saltwater algae is quite a difference.

vegedor2• 12 years ago

ATCV-1 exposure in mice also resulted in the altered expression of genes within the hippocampus. These genes comprised pathways related to synaptic plasticity, learning, memory formation, and the immune response to viral exposure.

KerrickStaley• 12 years ago

The researchers at this lab do lots of other interesting work: http://stanleylab.org/staff/

(Or at least things that have been hot on HN lately, e.g. Toxoplasmosis)

inglondon• 12 years ago

I posted this a few days ago here: https://news.ycombinator.com/item?id=8583393

oldspiceman• 12 years ago

Reminds me of that cat virus linked to schizophrenia. http://en.wikipedia.org/wiki/Toxoplasma_gondii

xico• 12 years ago

Knowing that most of the Western Europe people are infected by toxoplasma, it is hardly a ‘cat’ virus (well, maybe in the US were the contamination is low due to the low diversity and extreme cooking of the food).

jarin• 12 years ago

It's not a virus, it's a protozoan.

blackbagboys• 12 years ago

I suppose it would be a gross overreaction to rush out and try to get to tested for this virus?

gwern2• 12 years ago

Yes. I'm not sure how you would either, unless you have access to a genetics/microbiology lab and the expertise to cluster and interpret the data.

tomrod2• 12 years ago

Researchers found no connection between slower brain function and variables such as differences in sex, education level, income, race, and even cigarette smoking.

They have 92 observations. I don't think they have enough data to control for these sufficiently.

Scientists have located an algal virus that attacks human DNA

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