Tag Archives: evolution

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Sifting through the genes that make humans unique

AnimaBiologists used to think that new genes “could only evolve from duplicated or rearranged versions of preexisting genes.” Now, though:

Scientists have made a crucial discovery of genes that have evolved in humans after branching off from other primates, opening new possibilities for understanding what makes us uniquely human….

Researchers have found genes that arose from non-coding DNA in flies, , and primates. No such genes had been found to be unique to humans until now, and the discovery raises fascinating questions about how these genes might make us different from other primates….

The authors [David Knowles and Aoife McLysaght of the Smurfit Institute of Genetics at Trinity College Dublin] also note that because of the strict set of filters employed, only about 20% of human genes were amenable to analysis. Therefore they estimate there may be approximately 18 human-specific genes that have arisen from non-coding DNA during human evolution.

This discovery of novel protein-coding genes in humans is a significant finding, but raises a bigger question: What are the proteins encoded by these genes doing? “They are unlike any other human genes and have the potential to have a profound impact,” McLysaght noted. While these genes have not been characterized yet and their functions remain unknown, McLysaght added that it is tempting to speculate that human-specific genes are important for human-specific traits.

[Image: Dollar Bin]

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E.O. Wilson tells Will Wright: ‘Games are the future in education’

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dragonNational Public Radio just aired a wonderful conversation between Spore and Sims creator Will Wright and Harvard biologist E.O. Wilson, well worth a read or listen. But the chat didn’t go the way Wright thought it would:

I came into the interview with all these questions I wanted to ask him about evolution,” Wright said, “but his first response was, ‘Oh, I thought we were going to talk about games!'”

Wright wasn’t completely surprised. One of Wilson’s goals has been to “unify science with disciplines such as the humanities,” Wright said. “He is one of the few scientists who really has the guts to do that.”

So, asked by Wright about the role of games in education, Wilson said:

“I’ll go to an even more radical position,” Wilson said. “I think games are the future in education. We’re going through a rapid transition now. We’re about to leave print and textbooks behind.”

Wilson imagines students taking visits through the virtual world to different ecosystems. “That could be a rain forest,” he said, “a tundra — or a Jurassic forest.”

Wilson said that for the most part, we are teaching children the wrong way. According to the biologist, “When children went out in Paleolithic times, they went with adults and they learned everything they needed to learn by participating in the process.”

That’s the way the human mind is programmed to learn, Wilson said.

But he believes that today, virtual reality can be a steppingstone to the real world. It can motivate a child to exploration.

Wilson had a very different experience growing up. He explored the real world — and its creatures and plants — from a very young age. He credits his permissive parents and the schools he attended for allowing him to “disappear” into the forest.

“No one knew what I was doing,” he said.

Wilson is now studying the origins of altruistic behavior, taking his cue from Paul Gauguin: “Where did we come from? Who are we? Where are we going?” An education system that produces that kind of curiosity is the one I want for kids today.

Such ideas aren’t new to most of us, but it’s encouraging to hear them nudge their way towards conventional wisdom.

[Image: Torley]

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Depression may be evolution’s way of telling us to think things over

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hello“Mental disorders should generally be rare,” state researchers Paul W. Andrews and J. Anderson Thomson, Jr. ” — why isn’t depression?” It doesn’t seem to be a function of aging and culture, yet prescription drugs for it help keep pharmaceutical companies afloat.

There is another possibility: that, in most instances, depression should not be thought of as a disorder at all. In an article recently published in Psychological Review, we argue that depression is in fact an adaptation, a state of mind which brings real costs, but also brings real benefits…. So what could be so useful about depression? Depressed people often think intensely about their problems. These thoughts are called ruminations; they are persistent and depressed people have difficulty thinking about anything else. Numerous studies have also shown that this thinking style is often highly analytical. They dwell on a complex problem, breaking it down into smaller components, which are considered one at a time….

Many other symptoms of depression make sense in light of the idea that analysis must be uninterrupted. The desire for social isolation, for instance, helps the depressed person avoid situations that would require thinking about other things. Similarly, the inability to derive pleasure from sex or other activities prevents the depressed person from engaging in activities that could distract him or her from the problem. Even the loss of appetite often seen in depression could be viewed as promoting analysis because chewing and other oral activity interferes with the brain’s ability to process information.

But is there any evidence that depression is useful in analyzing complex problems? For one thing, if depressive rumination were harmful, as most clinicians and researchers assume, then bouts of depression should be slower to resolve when people are given interventions that encourage rumination, such as having them write about their strongest thoughts and feelings. However, the opposite appears to be true. Several studies have found that expressive writing promotes quicker resolution of depression, and they suggest that this is because depressed people gain insight into their problems.

The idea that depression–which the authors acknowledge is painful and can be serious–can have a purpose is a new idea to me.

I’m going to go lie in a dark room and think about it.

[Image: Somebody Needs a Hug by Robyn Gallagher]

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Intelligent design vs. natural selection

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flowerEric Drexler has written a paper entitled Biological and Nanomechanical Systems: Contrasts in Evolutionary Capacity that explores the differences between biological organisms and artificial machines, specifically why some products of intelligent design (i.e. design by humans) could never be created by natural selection. Drexler has written a short preface summarising his argument here:

The basic argument is as follows:

  • Evolvable systems must be able, with some regularity, to tolerate (and occasionally benefit from) significant, incremental uncoordinated structural changes.This is a stringent contraint because, in an evolutionary context, “tolerate” means that they must function — and remain competitive — after each such change.
  • Biological systems must satify this condition, and how they do so has pervasive and sometimes surprising consequences for how they are organized and how they develop.
  • Designed systems need not (and generally do not) satify this condition, and this permits them to change more freely (evolving in a non-biological sense), through design. In a design process, structural changes can be widespread and coordinated, and intermediate designs can be fertile as concepts, even if they do not work well as physical systems.

As I read it (and I could be wrong) the basic notion underlying Drexler’s argument is that the kind of mechanical precision demanded by human engineers is not present in the products of natural evolution. Artificial technologies are not yet fungible. If you remove any part of your CPU it will not work. If you remove some parts of someone’s brain then it still works. If you make a small alteration to an organism’s genome it may still work.

In order for evolution to work the replicator needs to function even when it has some small mutation. Artificial technologies generally don’t work when there is some small error in the manufacturing process.

[from Eric Drexler on Metamodern][image from bbjee on flickr]

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Why you have (or had) an appendix

CT scanThe image of the appendix has been getting a makeover. Two years ago, Duke U. researchers suggested it is not the useless evolutionary vestige that Darwin said it was.

The appendix, they said, is a safe haven where good bacteria could hang out until they were needed to repopulate the gut after a nasty case of diarrhea, for example.

Now some of the team suggest the appendix has been around a lot longer than Darwin thought.

[Surgical sciences professor William] Parker and colleagues found that the appendix has evolved at least twice, once among Australian marsupials and another time among rats, lemmings and other rodents, selected primates and humans. “We also figure that the appendix has been around for at least 80 million years, much longer than we would estimate if Darwin’s ideas about the appendix were correct.”

Parker says Darwin just didn’t have access to enough information about the organ.

“If he had known about the widespread nature of the appendix, he probably would not have thought of the appendix as a vestige of evolution.”

He also was not aware that appendicitis, or inflammation of the appendix, is not due to a faulty appendix, but rather due to cultural changes associated with industrialized society and improved sanitation. “Those changes left our immune systems with too little work and too much time their hands – a recipe for trouble,” says Parker.

[Story tip: Phoenix New Times blog; CT image by jellywatson]