jm + evolution   8

Brain Cells Share Information With Virus-Like Capsules - The Atlantic
...a gene called Arc which is active in neurons, and plays a vital role in the brain. A mouse that’s born without Arc can’t learn or form new long-term memories. If it finds some cheese in a maze, it will have completely forgotten the right route the next day. “They can’t seem to respond or adapt to changes in their environment,” says Shepherd, who works at the University of Utah, and has been studying Arc for years. “Arc is really key to transducing the information from those experiences into changes in the brain.”

Despite its importance, Arc has been a very difficult gene to study. Scientists often work out what unusual genes do by comparing them to familiar ones with similar features—but Arc is one-of-a-kind. Other mammals have their own versions of Arc, as do birds, reptiles, and amphibians. But in each animal, Arc seems utterly unique—there’s no other gene quite like it. And Shepherd learned why when his team isolated the proteins that are made by Arc, and looked at them under a powerful microscope.

He saw that these Arc proteins assemble into hollow, spherical shells that look uncannily like viruses. “When we looked at them, we thought: What are these things?” says Shepherd. They reminded him of textbook pictures of HIV, and when he showed the images to HIV experts, they confirmed his suspicions. That, to put it bluntly, was a huge surprise. “Here was a brain gene that makes something that looks like a virus,” Shepherd says.

That’s not a coincidence. The team showed that Arc descends from an ancient group of genes called gypsy retrotransposons, which exist in the genomes of various animals, but can behave like their own independent entities.* They can make new copies of themselves, and paste those duplicates elsewhere in their host genomes. At some point, some of these genes gained the ability to enclose themselves in a shell of proteins and leave their host cells entirely. That was the origin of retroviruses—the virus family that includes HIV.
brain  evolution  retroviruses  viruses  genes  arc  gag  proteins  memory  biology 
7 days ago by jm
Why are transhumanists such dicks?
Good discussion from a transhumanist forum (via Boing Boing):
"I’ve been around and interviewed quite a lot of self-identified
transhumanists in the last couple of years, and I’ve noticed many of them
express a fairly stark ideology that is at best libertarian, and at worst
Randian. Very much “I want super bionic limbs and screw the rest of the world”.
They tend to brush aside the ethical, environmental, social and political
ramifications of human augmentation so long as they get to have their toys.
There’s also a common expression that if sections of society are harmed by transhumanist
progress, then it is unfortunate but necessary for the greater good (the greater
good often being bestowed primarily upon those endorsing the transhumanism).

That attitude isn’t prevalent on this forum at all – I think
the site tends to attract more practical body-modders than theoretical transhumanists
– but I wondered if anyone else here had experienced the same attitudes in
their own circles? What do you make of it?"
transhumanism  evolution  body-modding  surgery  philosophy  via:boingboing  libertarianism  society  politics 
march 2015 by jm
#AltDevBlog » Parallel Implementations
John Carmack describes this code-evolution approach to adding new code:
The last two times I did this, I got the software rendering code running on the new platform first, so everything could be tested out at low frame rates, then implemented the hardware accelerated version in parallel, setting things up so you could instantly switch between the two at any time.  For a mobile OpenGL ES application being developed on a windows simulator, I opened a completely separate window for the accelerated view, letting me see it simultaneously with the original software implementation.  This was a very significant development win.

If the task you are working on can be expressed as a pure function that simply processes input parameters into a return structure, it is easy to switch it out for different implementations.  If it is a system that maintains internal state or has multiple entry points, you have to be a bit more careful about switching it in and out.  If it is a gnarly mess with lots of internal callouts to other systems to maintain parallel state changes, then you have some cleanup to do before trying a parallel implementation.

There are two general classes of parallel implementations I work with:  The reference implementation, which is much smaller and simpler, but will be maintained continuously, and the experimental implementation, where you expect one version to “win” and consign the other implementation to source control in a couple weeks after you have some confidence that it is both fully functional and a real improvement.

It is completely reasonable to violate some generally good coding rules while building an experimental implementation – copy, paste, and find-replace rename is actually a good way to start.  Code fearlessly on the copy, while the original remains fully functional and unmolested.  It is often tempting to shortcut this by passing in some kind of option flag to existing code, rather than enabling a full parallel implementation.  It is a  grey area, but I have been tending to find the extra path complexity with the flag approach often leads to messing up both versions as you work, and you usually compromise both implementations to some degree.

(via Marc)
via:marc  coding  john-carmack  parallel  development  evolution  lifecycle  project-management 
june 2014 by jm
Common phobia you have never heard of: Fear of holes may stem from evolutionary survival response
"We think that everyone has trypophobic tendencies even though they may not be aware of it," said Dr Cole. "We found that people who don't have the phobia still rate trypophobic images as less comfortable to look at than other images. It backs up the theory that we are set-up to be fearful of things which hurt us in our evolutionary past. We have an innate predisposition to be wary of things that can harm us."
trypophobia  holes  fear  aversion  disgust  ugh  evolution  innate 
september 2013 by jm
Pruney fingers grip better : Nature News
The hypothesis, from Mark Changizi, an evolutionary neurobiologist at 2AI Labs in Boise, Idaho, and his colleagues goes against the common belief that fingers turn prune-like simply because they absorb water. Changizi thinks that the wrinkles act like rain treads on tyres. They create channels that allow water to drain away as we press our fingertips on to wet surfaces. This allows the fingers to make greater contact with a wet surface, giving them a better grip.'
science  anatomy  grip  evolution  water  biology  from delicious
july 2011 by jm
Using genetic algorithms to find Starcraft 2 build orders
discovered a previously-unknown optimal build strategy for the Zerg race -- how cool is that
zerg-rush  starcraft  ga  genetic-algorithms  evolution  gaming  coding  from delicious
november 2010 by jm
Exploring the Spam Arms Race to Characterize Spam Evolution
from last week's CEAS conference; research comparing SpamAssassin releases against the evolution of the surrounding spam environment. Nice work, I always wanted to write up something like this (via JD)
spam  anti-spam  ceas  conference  papers  research  spamassassin  adversarial-classification  evolution  arms-race  via:jd  from delicious
july 2010 by jm
TCD researchers first to find genes unique to humans
go Aoife! “This is the first ever discovery of novel human-specific protein coding genes,” said Dr McLysaght. “They are found in humans and nowhere else.”
science  genetics  research  biology  evolution  tcd  sfi  genome  junk-dna  from delicious
september 2009 by jm

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