Mental Health Awareness

I am running in the Ottawa Race Weekend for a great cause. I lost a very dear friend to mental illness last year and would like anyone that can donate and/or pass this link along to others to please do so. In donating, you are helping raise awareness for not only the countless others who suffer from mental illness, but helping tear down the social stigma that surounds it. Davi Freire was a beautiful soul and a brilliant mind that will forever be missed. I cannot change the decision that Davi made, but in his memory, I hope you will help me so that others may not endure the same suffering.
In aiding The Royal we are fighting against Mental Illness — specifically major depression — is the single greatest cause of disability in our society today. Apart from the financial burden, the human cost is enormous. Normal healthy lives are devastated. Families are torn apart. This disease of the mind takes, and takes, and takes… I want to GIVE and hope you do too to help The Royal transform the lives of those suffering from mental illness with innovative and effective treatments, and to identify new methodologies for prevention and early detection.

Please click on the link below and Donate Now.

http://t.co/loGRbc4y

Thank you from the bottom of my heart.

-Meghan

PLEASE FEEL FREE TO REBLOG

#mental health awareness

UPDATE: Vancouver Safe Injection Site Gets Supreme Court OK

UPDATE: Vancouver Safe Injection Site Gets Supreme Court OK
September 30, 2011
Update: Wow. In a bold decision today, the Supreme Court of Canada has ruled that InSite, the supervised injection facility for addicts located in Vancouver’s troubled Downtown Eastside, will be allowed to continue to operate. 

InSite was opened in 2003 under an exemption from federal drug laws. The current federal government attempted to let that exemption lapse - a way to shutter the operation - but the court today instructed the government to continue to grant the exemption, as InSite “has proven successful”.

"Insite has saved lives and improved health without increasing the incidence of drug use and crime in the surrounding area. It is supported by the Vancouver police, the city and provincial governments," the court wrote in its ruling.

"Its benefits have been proven," the ruling also said. "There has been no discernable negative impact on the public safety and health objectives of Canada during its eight years of operation."

The current federal government’s position on InSite was reflected in former Minister of Health Tony Clement’s remarks at the XVII International AIDS Conference conference in Mexico City in 2008: “Allowing and/or encouraging people to inject heroin into their veins is not harm reduction, it is the opposite. We believe it is a form of harm addition.” The Conservatives also argued that resources would be better spent on prevention and tougher drug laws.

InSite was the first such facility in North America. Today’s ruling suggests that similar safe injection sites could be opened in other provinces across the country.


Canada’s Supreme Court to Rule on Injection Site
September 28, 2011

This Friday at 9:45am EDT, the Supreme Court of Canada is expected to render a decision on whether Vancouver’s safe injection program will be allowed to continue to operate.

Supported by the City of Vancouver, the government of BC, and Vancouver Coast Health, InSite is North America’s first legal supervised injection site. Drug users who participate at InSite can safely inject intravenous drugs with clean needles while being advised about health care services and addiction treatment programs.

A study published in a British medical journal in April 2011 - with research from the BC Centre for Excellence in HIV/AIDS - found that overdose fatalities dropped by 35% since InSite first began operating in Vancouver’s Downtown Eastside, an area whose drug problems have been well documented.

InSite was opened in 2003 with exemptions from federal drug laws. The exemptions were first provided by the then-Liberal federal government, and continued in 2006 under the Conservatives. However, in 2008, the Conservative government sought to deny further exemptions for the program, setting up a series of lower court decisions (in favour of InSite) and appeals (by the government) that have led up to Friday’s announcement.

(Source: )

Toxic Gulf: BP’s Disaster


As someone’s hopefully told you, for the last month and a half a 2-foot-wide pipe in the Gulf of Mexico has been ejaculating oil to the tune of half a million gallons a day. We went down to Louisiana over Memorial Day to see some of the damage for ourselves.

See the rest at VBS.TV: TOXIC: Gulf Full Length - Toxic | VBS.TV 

The Future of Brain Transplants

  • By Peter Tyson
  • Posted 08.26.10
  • NOVA scienceNOW

Will we ever grow replacement brains or do whole-brain transplants?

Need a new body part? Tissue engineers are now growing human bladders, lungs, and other organs in the lab with the hope that, someday soon, such organs may replace diseased organs in people. Transplant surgeons, for their part, routinely place donated kidneys, hearts, and other organs into patients whose own organs are failing. They have transplanted hands, arms, even, famously, a face.

This has left me wondering, where does the brain come into all this? Will we someday grow replacement brains or do whole-brain transplants? Three questions leap to mind: Why would we? Could we? And should we?

brain in hands

On bad days, we may feel we’d like a brain transplant, but what are the prospects realistically? Some experts have actually put their minds to it.EnlargePhoto credit: © Henrik Jonsson/iStockphoto

I must admit to feeling a bit squeamish with the whole idea, which you might agree has a sizeable “yuck” factor. And I felt a little sheepish when I called experts to ask them about it. Would they dismiss me out of hand, beseeching me not to waste their time with a subject best left to science-fiction writers? But with science and medicine advancing at a dizzying pace, and with questionable medical procedures of the past as cautionary tales, it seemed like a subject worth addressing, if only perhaps to reject it as untenable, unconscionable, or simply too ghastly to contemplate.

WHY WOULD WE?

First of all, why? What medical justification could exist for growing a new brain, or part of one, and placing it in someone whose own brain, or part of it, was removed?

"Certainly there are situations where people have tumors and have to have areas resected or situations where people are brain-dead," says Doris Taylor, whose tissue-engineering lab at the University of Minnesota’s Stem Cell Institute is experimenting with growing entire replacement organs, including 70 livers last year alone. "Certainly there are situations where somebody has an accident that leaves their brain stem injured. Would it be nice to be able to regrow the appropriate regions? Absolutely. Talk to any paraplegic or quadriplegic out there. They would love to have new cervical neurons or brain-stem regions."

Other researchers echoed Taylor’s sentiments—that the future of brain tissue engineering likely concerns small pieces, not the whole enchilada.

communicating neurons

Trying to make or reestablish tiny connections in the brain, even between single neurons, is closer to reality than growing whole brains, tissue engineers say.EnlargePhoto credit: © Sebastian Kualitzki/iStockphoto

"We’re not going to make whole brains in a dish and then just transplant them," says Evan Snyder, head of Stem Cells and Regenerative Biology at the Sanford-Burnham Medical Research Institute in California. "But what people are playing with is, is it possible to do little bits of tissue engineering in a dish and then put these tissues into small areas [of the body] and see whether you can make some connections?" Perhaps help a patient with Parkinson’s disease regain some lost neural functionality, say, or buy a quadriplegic another segment of spinal cord function such that she can breath a little better on her own or can now move her thumbs—that’s the hope, Snyder says.

"Building a whole brain? That’s kind of out there."

What about transplanting existing brains from one individual to another, like we do with donated hearts or kidneys? Under what scenario would we consider that? About a decade ago, Dr. Robert White, a neurosurgeon at Case Western Reserve University, received a burst of media attention by advocating what he called “whole-body transplants” for quadriplegics. (Because the brain can’t function without the head’s wiring and plumbing, White noted, a brain transplant, at least initially, would be a head transplant. And, perhaps because of the yuck factor, he preferred to call such an operation a whole-body transplant.)

Quadriplegics often die prematurely of multiple-organ failure, White said. If surgeons could transfer the healthy body of a donor, such as a brain-dead individual or someone who has just died of a brain disease, to the healthy head of a quadriplegic, they could prolong that patient’s life. Brain-dead patients already serve as multiple-organ donors, so a whole-body transplant is not as macabre as it might at first sound, White argued.

MRI of head

Could surgeons detach a living human head (brain included) and place it on the living body of a donor? Robert White says it’s possible—and may be in our future.EnlargePhoto credit: © Luis Carlos Torres/iStockphoto

I tracked down Dr. White, who is now retired after 60 years as a brain surgeon but is still active as a writer and consultant. “I think this is an operation of the future,” he told me on the phone. “But it is certainly out there, and under these circumstances [of quadriplegia], the concept of giving somebody who is important or quite young a new body is not beyond comprehension.” And it should be discussed now, White feels, because it may well be coming. “We’re still within just the first 100 years of transplantation,” he said. “Who knows where we’ll be after another 100 years?”

COULD WE GROW NEW BRAINS?

Let’s say for the sake of argument that we had sound medical reasons for doing such procedures. Could we, technically speaking? Could we grow a whole human brain, or even part of one, in a laboratory?

"There is now data showing that if you put stem cells in an area of brain injury that the cells actually home into the injured brain area, and they can take up residence there and exhibit some sort of functionality," says Tony Atala, director of the Wake Forest Institute for Regenerative Medicine and head of one of the premier tissue-engineering labs in the country. "But building a whole brain? That’s kind of out there." How about a single lobe? "That would be extremely complex to do," he said. "As a scientist, you never say never, because you never know what will be within the realm of possibility several centuries from now. But certainly to replace a lobe today, that would be science fiction with current technology."

Doris Taylor was more willing to speculate but was also cautious. “We can decellularize the brain,” she told me, referring to her lab’s technique to chemically strip all cells from donor organs, leaving a kind of cell-less scaffold that can be seeded with stem cells and “regrown.” “But whether it’s possible to restore brain cells appropriately, who knows?” She paused. “And in the case of the brain, how would you know? There’s such a wide spectrum of behavior and functioning. I’m not sure we’d ever have an end point to know how to measure.” She paused again. “I have no doubt that we can rebuild at least some neural pathways. The question is, will that rebuild a brain, including everything you need for mind-brain function, or even a piece thereof? I really don’t know.”

Taylor envisions more modest steps forward, such as rebuilding small parts of the brain to decrease the size or frequency of seizures in an epileptic or to help restore some functionality in a stroke victim who had suffered severe neurologic loss. “I could imagine considering growing regions of brains to graft in,” she says. “But are we within five to ten years of that? That’s hard to imagine.”

head and spine graphic

While the focus of intensive research, successfully reconnecting the spinal cord to the brain following a serious spinal injury remains beyond current science. EnlargePhoto credit: © Mads Abildgaard/iStockphoto

Research with neural stem cells has shown that it’s extremely hard to make even the simplest neuronal connections, much less regenerate neurons, as had been hoped early on. “The vision of the stem cell field 20 years ago was you have a patient in a wheelchair and you stick a stem cell into his brain or spinal cord, and he’ll come bounding out of his wheelchair and run the Boston Marathon,” Snyder says. “We know now that’s not the way it’s going to happen.”

COULD WE TRANSPLANT EXISTING BRAINS?

What about a head transplant—or, if you prefer, a whole-body transplant? Doable? White thinks it is, even as he acknowledges that the financial costs would be prohibitive.

"Could you keep an isolated human head alive? That’s creepy. Very creepy."

"I’ve had plenty of time to think about it, and the operation itself, although complex, really involves structures in and about the neck," White told me. "You’re not cutting into the brain, and you’re not cutting into the body, just severing everything at the neck. It’s a very complex operation, because you have to make sure that the body’s kept alive and the head’s kept alive. But this has all been worked out in smaller animals."

Forty years ago, in studies that to some commentators smacked of Dr. Frankenstein, White and his team experimented with transplanting the newly detached head of a live rhesus monkey onto the body of another monkey that had just had its head removed. The longest-lived such hybrid, which reportedly showed unmistakable signs of consciousness, lasted eight days.

head with brain

All the surgery involved in a head transplant would take place in and around the neck, White says. While mind-numbingly complex, such an operation is conceivable, he argues.EnlargePhoto credit: © Max Delson Martins Santos/iStockphoto

"With the significant improvements in surgical techniques and postoperative management since then," White wrote in a 1999 Scientific American article, "it is now possible to consider adapting the head-transplant technique to humans." White acknowledges that a quadriplegic who got a new body today would remain paralyzed below the neck, because successfully reconnecting the brain to the spinal column remains beyond our reach.

"That’s a very interesting scenario," Taylor said when I brought up White’s idea. But would it work? "Well, technically, people can do almost anything," she said. "You can sew something the size of or smaller than a human hair, so technically I could imagine that working. But there are huge things we still don’t know and have to learn. That doesn’t mean that I can’t imagine doing all of this. It does mean that I’m going to ask some difficult questions before I say it’s ready for prime time or even clinical utility."

Snyder was also willing to consider possibilities, though for him the yuck factor loomed large. The first step, he felt, would have to be the ability to sustain a head independent of a body, even for a short period. “Could you keep an isolated human head alive such that it’s thinking and talking and all we need to do is perfuse it with the right chemicals and the right nutrients and keep the acid-base balance fine?” he said. “That’s creepy. Very creepy.” Agreed, but how soon? “I can’t say it’s absolutely impossible,” he said. “But I don’t see that happening in the next 100 years.”

SHOULD WE TRANSPLANT EXISTING BRAINS?

One expert who has given a lot of thought to the notion of head transplants—and was not a bit hesitant to talk about them—is Paul Root Wolpe, a bioethicist at the Emory Center for Ethics at Emory University. (In fact, he once debated White on the subject on radio.)

blue head among gray

"I’m always wary of the valuable-people argument," says Paul Root Wolpe, about the idea of singling out individuals for life-prolonging head transplants because of their "importance."EnlargePhoto credit: © ktsimage/iStockphoto

Wolpe has several problems with the concept, he told me. One concerns use of resources. Referring to a putative head transplant, he said, “The desperate attempt to keep individuals alive using more and more resources seems to me to be extraordinarily misguided when you’re talking about a world where people are dying for lack of resources, very preventable kinds of diseases and issues like malnutrition.” The idea that it could prolong the life of someone deemed important did not sit well with him. “I’m always wary of the valuable-people argument—’Forget keeping not-valuable people alive, that’s kind of a waste, but what if we could keep valuable people alive?’ I have a lot of trouble when I put the argument that way.” Wolpe would consider a whole-body transplant, he says, “a fundamental ethical transgression.”

Another concerns a person’s bodily integrity. “You are talking about a fundamental kind of change whereby a body becomes simply a means of supporting a head, where your sense of what it means to be a whole human being has been compromised in a very new way,” he says. Wolpe believes this change to be intrinsically different than that brought about by heart transplants, which, when such operations first started taking place, did raise a host of questions in people’s minds about what it would mean for a recipient’s sense of wholeness.

"Who do we grow a new brain for? I’m not sure of the medical problem that that solves."

One’s very sense of selfhood would be at stake, Wolpe argues. In the West we tend to think of the brain as the locus of self, but culturally that is a very new idea, and it’s still not shared in many cultures, he says. Consider Japan, where the locus of self is thoracic and abdominal. “That’s why when you commit seppuku you disembowel yourself, you don’t cut your head off, because you’re attacking yourself at the seat of selfhood,” he told me.

The notion that if you put his head on someone else’s body that the resulting individual would be him and not the other person simply because the hybrid had his brain is, Wolpe says, “theory not fact, a philosophical position rather than a scientific reality. What you may end up finding is that when you transfer a brain from one body to another, the resulting organism is not solely what one would think of as the person whose brain it was but also has enormous components of the person into whose body it goes.”

Altogether, the ethical issues surrounding head transplantation are insurmountable, Wolpe feels.

head with padlock

"Don’t go there" would seem to be the position of most experts when it comes to contemplating the transplantation of human brains, either nature- or lab-born.EnlargePhoto credit: © ktsimage/iStockphoto

SHOULD WE GROW NEW BRAINS?

As for growing brains, Wolpe has a hard time seeing how you could justify it medically. “Who do we grow a new brain for? Do we grow it for someone with Alzheimer’s? Do we grow it for someone with a severe brain tumor?” I didn’t need to ask him to speculate. “Say you had a severe brain tumor, and I took a stem cell from you and I grew a new brain for you and got rid of your old brain and put in your new brain, none of you would be there. Your memories, your ideas, your thoughts, your thinking of your wife as your wife and your kids as your kids—it’s all gone, unless we can also transfer all your memories, thoughts, and ideas to a new brain.

"So I’m not even sure what a brain transplant means in that context," he continued. "It means wiping the slate clean and now having a pre-birth-level brain in a 60-year-old person or whatever? I’m not sure of the medical problem that that solves."

A LOAD OFF

Wouldn’t, couldn’t, shouldn’t—that seems to be the general consensus for both growing and transplanting human brains, at least for the forseeable future. That’s a relief—my head hurts just thinking about them.

Ten Great Advances in Evolution

  • By Carl Zimmer
  • Posted 10.26.09
  • NOVA

To celebrate the 150th anniversary of the Origin of Species, here’s a list—by no means exhaustive—of some of the biggest advances in evolutionary biology over the past decade. These advances include not just a better understanding of how this or that group of species first evolved, but insights into the evolutionary process itself. In some cases those insights would have given Darwin himself a pleasant jolt of surprise.

Ten significant leaps forward in evolution research in the past decade, as chosen and described by noted science writer Carl Zimmer EnlargePhoto credit: (Earth) © NASA; (text) © WGBH Educational Foundation

 

EVOLUTION IN ACTION

Darwin envisioned natural selection acting so slowly that its effects would be imperceptible in a human lifetime. But in the late 1900s, evolutionary biologists began to detect small but significant changes taking place in a handful of species. In the past decade, many more cases of natural selection have come to light, and scientists now realize that species can adapt quickly to changes in their environment. In fact, they are finding that we humans are unwittingly driving some of the fastest bursts of evolution right now. As greenhouse gases drive up the planet’s average temperature, for instance, some species are adapting to the changing climate. In California, University of Toronto biologist Arthur Weis and his colleagues found that a seven-year drought had spurred the evolution of field mustard plants. In 2007, they reported that the plants were now genetically programmed to flower eight days earlier in the spring.

Charles Darwin

If he were alive today, Darwin would be astonished at the pace and nature of discoveries being made in evolutionary biology, including the witnessing of evolution in action.EnlargePhoto credit: © Louie Psihoyos/Science Faction/Corbis

 

Thanks to powerful, cheap DNA sequencing technology, scientists can now pinpoint the molecular changes underlying this rapid evolution. Bernard Palsson and his colleagues at the University of California in San Diego have observed bacteria evolve in their lab. Over the course of a few weeks, the bacteria adapted to a new kind of food (a chemical called glycerol). The scientists sequenced the complete genome of the ancestral germ and its evolved descendants and looked for differences in their DNA. They identified a handful of new mutations that has arisen in the bacteria and spread throughout the population. When the scientists added those mutations to the ancestral germ, it became able to feed on the new food just as its descendants did.

TRANSITIONAL FOSSILS

Darwin argued that even though different groups of species today might seem very different from each other, they were linked by common ancestry. His theory predicted the existence of species that would document that link. Just a year after the Origin of Species was published, Darwin was gratified to learn of the discovery of a bird calledArchaeopteryx that did just that. While it had feathers and wings, it also had reptilian traits not seen in living birds, such as a long tail and claws on its “hands.” It’s too bad that Darwin was not around to read the news about transitional fossils discovered just in the past decade. Many have been just as spectacular as Archaeopteryx, if not more so.

Tiktaalik

Tiktaalik, here as depicted by artist Carl Buell, represents a key transitional creature between marine- and land-dwelling animals. EnlargePhoto credit: Courtesy Carl Buell

 

In 2004, for example, scientists digging in the Arctic unearthed the fossil bones of a fishy relative of all land vertebrates, including us, calledTiktaalik. This 375 million-year-old animal had limbs complete with elbows, wrists, and a flexible neck. But it still lived underwater, where it used its gills to breathe. [For more on Tiktaalik, see “The Zoo of You” (in Editors’ Picks at left).]

Whales in particular intrigued Darwin, because they were clearly mammals on the inside yet were so fish-like on the outside. In 1994, paleontologists reported the first fossil of a whale with legs, as Darwin had predicted. And over the past decade, they’ve uncovered a number of new fossils that fill in many of the details in the transition that whales made from land to sea between 50 and 40 million years ago.

For example, in 2001, Philip Gingerich of the University of Michigan and his colleagues reported the first ankle bone of a whale. This bone is particularly important to tracing the origin of whales, because it had a distinctive shape seen only in one group of mammals: even-toed hoofed mammals known as artiodactyls. Studies on whale DNA also completed over the past decade have consistently pointed to artiodactyls—and hippos in particular—as the closest living relatives of whales on land.

ORIGIN OF COMPLEX TRAITS

Studying DNA doesn’t just help scientists figure out which species are most closely related to one another. They can also discover how genes build structures like eyes in different species. That comparison has, in just the past decade, revealed some key insights into how those structures arose.

Eye diversity diagram

Complex eyes have evolved in several different lineages of animals. But each kind of eye contains crystallins for directing incoming light and opsins for capturing it.EnlargePhoto credit: (diagram) Echo Medical Media; (jellyfish) © ANT Photo Library/Photo Researchers Inc.; (octopus) © Kerry L. Werry/Shutterstock; (fly) © Stana/Shutterstock; (human eye) © Bplucinski/Shutterstock

 

Complex eyes evolved in a number of different lineages of animals, such as vertebrates like us, octopi and other cephalopods, and insects. For decades, the evidence suggested that these complex eyes had evolved independently in each lineage. Today, however, scientists see a much more intertwined history.

In 2007, for example, Todd Oakley of the University of California at Santa Barbara and his colleagues demonstrated that the different kinds of light receptors evolved from simple signal-detecting proteins in our distant ancestors some 600 million years ago. By the time early animals had evolved, these signal detectors had evolved into two different kinds of light receptors. Those early animals probably had eyes that were nothing more than simple light-sensitive spots. Only later did complex eyes evolve, and different lineages recruited different kinds of light receptors to capture images. Studies like Oakley’s indicate that complex eyes did indeed evolve independently, but they also co-opted many of the same ancient genetic tools to do so.

It’s a pattern that’s strikingly similar to the one other scientists have discovered in other traits in the past decade, from bird feathers to beetle horns: Evolution is the great recycler.

THE GENOMIC WILDERNESS

Natural selection, as Darwin recognized, is an important force in evolution. And in the past decade, scientists studying genes have found many examples of its power. When mutations change the way a protein-coding gene works—altering the structure of the protein, for example, or the signals that turn the gene on and off—those mutations can help or harm an organism’s reproductive success. Beneficial mutations can then spread, and over time they can transform a species dramatically.

DNA mutations

DNA can experience a number of different kinds of mutations, several of which are shown here. EnlargePhoto credit: © Lineworks

 

But natural selection is far from the full story of evolution. Many mutations can spread throughout an entire species thanks not to natural selection but through lucky rolls of the genetic dice. This so-called neutral evolution has been particularly important in shaping the parts of the genome that do not contain protein-coding genes. Most of the news you read about DNA concerns protein-coding genes, so you might well think that there’s not much of the genome that doesn’t contain them. But just the opposite is true. Some 98.8 percent of the human genome is this so-called noncoding DNA.

Only in the past few years have scientists started to explore this genomic wilderness in great detail, and they’ve used evolution as their guide. In the human genome, for example, there are an estimated 11,000 so-called pseudogenes—stretches of DNA that once encoded proteins but no longer do so thanks to disabling mutations. These vestiges of genes once had important functions, such as synthesizing vitamins or allowing us to smell certain molecules. Scientists know that these pseudogenes were once full-blown protein-coding genes, because they can find related versions of them in our primate relatives, in good working order.

Evolution lets scientists find needles in the genomic haystack.

While some of your noncoding DNA started out as your own genes, much more of it started out in invading viruses. Certain kinds of viruses can insert their DNA into host cells in such a way that it gets carried down from one generation of host to the next. Eventually these in-house viruses mutate so much they can no longer infect a new host. But they can still make copies of themselves, which get inserted into their old host’s genome. About 40 percent of the human genome is made up of this viral DNA. Scientists can trace the ancestry of this virus DNA by comparing its remnants in our own genomes to the ones left in other primates.

Much of this viral DNA has now mutated to such a degree that it has become little more than padding in the genome. But even these inert relicts hold clues to their past. All human beings carry versions of an ancient virus called HERV-K. The differences in those versions evolved after the original virus infected a single human and was then passed down to his or her descendants. French scientists compared these versions of HERV-K, tallying up the mutations in one. Based on those new mutations, the scientists estimated that the virus first infected a human ancestor a few million years ago.

To prove that it had indeed once been a full-fledged virus, the scientists then used the different versions of its DNA to infer what its original genetic sequence had been. They synthesized that piece of DNA and injected it into human cells. The synthesized DNA hijacked the cells and caused them to spew out viruses with the same genetic sequence. The scientists, in other words, had brought a dead virus back to life.

red blood cells

Parts of genes within, say, a red blood cell serve as switches, telling other genes when to turn on or off, and for how long (see “Gene Switches” in Editors’ Picks). EnlargePhoto credit: © Micro Discovery/Corbis

 

Sprinkled among the dead virus DNA and disabled pseudogenes are some useful elements of noncoding DNA. Some of these elements are switches, where proteins can attach to turn neighboring genes on and off. Our genome also contains stretches of DNA that can produce RNA molecules, but no proteins. These RNA molecules have their own essential roles to play in our lives, for example as signal detectors and gene regulators.

Scientists rely on evolution to find these elements as well. If a piece of noncoding DNA has no important function, mutations to it will have little effect on the survival of the organism that carries it. But if it does have an essential function, mutations will be far more likely to cause devastating harm. As a result, organisms with those harmful mutations will have fewer offspring, and so the piece of DNA will not change as easily. Scientists can find these functional elements by comparing many different species and looking for stretches of noncoding DNA that are unusually similar from species to species. In many cases, they’ve been able to demonstrate that these elements do indeed play crucial roles in the survival of organisms. Evolution thus lets scientists find needles in the genomic haystack.

THE POWER OF SEX

Darwin himself recognized that sex created an evolutionary force as powerful as natural selection. If animals have traits that members of the opposite sex find attractive—be they horns, feathers, or bright blue posteriors—those traits will become more common over the generations.

peacock tail feathers

Darwin came up with his theory of sexual selection to explain the peacock’s over-the-top tail feathers, among other extravagant physical traits in animals. EnlargePhoto credit: © Lee Pettet/istockphoto

 

The past decade of research has confirmed that sex is indeed a potent force. But it’s powerful in ways that Darwin could not have appreciated. Studies in the past few years have demonstrated that the sexual preference that females have for one kind of male over another is potent enough to carve an old species apart into several new ones. In the lakes of East Africa, for instance, sexual selection has driven the origin of hundreds of new species from fish that live and breed side by side.

Sexual selection does more than favor the sexy, however. Any adaptation that enables an individual to have more offspring than other members of its own sex may be favored by sexual selection. For example, male flies that inject chemicals along with their sperm into females can make them less receptive to mating with other males. Unfortunately for the females, these chemicals are toxic. So the female flies respond by evolving defenses against the chemicals, which the males then evolve strategies to overcome. Scientists have documented this so-called sexual conflict in great detail in the past decade, and they can even see its fingerprints on millions of years of evolution by measuring how quickly different genes have evolved. Some of the fastest-evolving genes build semen proteins in many species (including humans).

COEVOLUTION OF LOCKS AND KEYS

Darwin made one of his gutsiest predictions when he heard about a bizarre orchid in Madagascar called Angraecum sesquipedale. It grew a tube-shaped spur on its flower measuring over a foot long, at the bottom of which it produced nectar. Darwin was convinced that the extravagant shapes and colors of flowers evolved not to please the eye of man, but to use pollinating animals in many clever ways to promote the plants’ own reproduction. One common strategy Darwin recognized was the way a flower would dust insects with pollen as they drank up its nectar. So Darwin proposed that somewhere in the forests of Madagascar lived an insect with a tongue long enough to drink up A. sesquipedale's well-hidden nectar. As the mystery insect drank, the orchid's pollen would cover its body pressed against the flower.

Angraecum sesquipedale

Angraecum sesquipedale has cut a symbiotic deal with a species of long-tongued moth in its native Madagascar. Other such matches are not so mutually beneficial.EnlargePhoto credit: © 2004 Prem Subrahmanyam, used with permission/www.orchidstockphotos.com

 

Twenty-one years after Darwin’s death, his prediction came true. A moth with a foot-long tongue turned up in Madagascar.

We depend on ecosystems for many services, and in many cases those services are only possible thanks to coevolution.

Since then, scientists have discovered many other extreme matches in nature. Not all of them are so friendly as the one between the orchid and its long-tongued pollinator. Rough-skinned newts in western North America produce poison in their skin powerful enough to kill a crowd of people. The toxins do their damage by latching onto a particular receptor on the surface of neurons, disabling them. The reason for the newt’s overkill is its predator, the garter snake. Garter snakes make special versions of the receptor in question, with a shape that thwarts the toxin’s attachment. This precise defense allows the snake to dine on newts with impunity.

In the past decade, this back-and-forth kind of evolution, known as coevolution, has come much more sharply into focus. For example, scientists have long puzzled over exactly how intimate partnerships like the one between Darwin’s moth and orchid came about. In 2005, John Thompson of the University of California at Santa Cruz offered a theory, which he called the geographic mosaic model of coevolution. Thompson argued that, in some places, two species will drive each other’s evolution towards more extreme adaptations, while in other places, they may have little or no effect on each other. At the same time, individuals are steadily moving from one population to another, carrying their coevolved genes. Rather than just evolving in lockstep, coevolutionary partners actually evolve in a complex fashion, which Thompson called a geographic mosaic.

rough-skinned newt

The rough-skinned newt has long been in an evolutionary arms race with the garter snake, to the point where its skin has become extremely toxic. EnlargePhoto credit: © Visuals Unlimited/Corbis

 

Remarkably, it only took a few years for scientists to test Thompson’s model—and find support for it. Some looked at pine trees and birds that spread their seeds, others at bacteria and the viruses that infect them, still others at the rough-skinned newts and their garter snake predators. In each case, they discovered an intricate landscape of coevolutionary hotspots and coldspots, just as Thompson predicted.

Insights like these are some of the most important in evolution, particularly for our own well-being. We depend on ecosystems for many services, and in many cases those services are only possible thanks to coevolution. Many of the plants we depend on for food and building materials, for example, have coevolved with fungi that help them get nutrients out of the soil. They also depend on pollinating animals in many cases to reproduce. We, too, have coevolved with friendly microbes and harmful ones (see “Evolutionary medicine” entry).

EXTINCTION’S FOOTPRINT

Unfortunately, over the past decade, it has become increasingly clear that the world’s biodiversity is imperiled on a scale unmatched for millions of years. As forests are cleared, oceans acidified, diseases spread, and the atmosphere warmed, many species face serious threats to their survival. While this wave of extinctions is new, the history of life has seen many pulses in which vast numbers of species have been wiped out. Studies on extinction are revealing that it has a profound influence on the evolutionary process itself, reorganizing entire ecosystems and offering new opportunities for surviving species to exploit the niches left empty by vanished ones.

Earth from space

Our planet has suffered five mass extinctions in the roughly three billion years since life first evolved. Many scientists believe it is now facing its sixth, this one caused by us. EnlargePhoto credit: © NASA

 

Volcanoes in particular appear to have wreaked a lot of havoc, warming the planet with heat-trapping gases and helping to trigger drastic changes in the ocean’s chemistry. Under some circumstances, these kinds of assaults can trigger ecological collapse.

It can take millions of years for the planet to recover from mass extinctions, and in some important ways it is never quite the same. Some of the groups of species that once dominated the planet were snuffed out in mass extinctions. In the past decade, scientists have seen major shifts in the planet’s ecology—particularly in the oceans—that hint that it is in the midst of yet another reorganization. As coral reefs die off and fish are hauled out of the sea, for example, less familiar forms of life such as jellyfish or even sulfide-belching bacteria may come to dominate the seas.

THE TREE AND THE WEB

Now that we live in the genome age, scientists are getting an unprecedented look at how species evolved from common ancestors. That’s because their common ancestry is recorded in their DNA, which is passed down from generation to generation. Using supercomputers and sophisticated new statistical methods to analyze DNA, scientists can test old hypotheses about how species are related to one another. They are starting to resolve some puzzles that previous generations of scientists simply couldn’t crack. Paleontologists have long argued, for example, that our closest living aquatic relatives are lungfishes and coelacanths, a conclusion that geneticists now confirm. Among our primate relatives, chimpanzees and bonobos are now widely recognized as our closest living kin.

three domain tree

A tree of life drawn from DNA studies, with length denoting number of mutations in each branch. Note how animals comprise a very small part of the genetic diversity of life on Earth.EnlargePhoto credit: © Lineworks

 

DNA is not a magic wand that instantly gives us answers to all our questions, however. At some stages in the evolution of life, many new lineages have evolved over a relatively short period of time. Many of the major groups of animals alive today may have evolved over roughly 50 million years, some 550 million years ago. It can be difficult to make out the details of these periods of life’s history, much as it’s hard to use a telescope to make out individual people on a distant island.

Scientists have found that fungi and animals share a closer ancestry than either does to plants.

At the same time, DNA is revealing new patterns in the history of life. Darwin first envisioned evolution as a tree, with new branches budding off like young branches. Today, that metaphor still has great power to explain. Chimpanzees and bonobos are two branches joined at the base by a common ancestor about two million years ago; our own branch split off from their lineage about seven million years ago. On a far grander scale, scientists have found that fungi and animals share a closer ancestry than either does to plants.

But genes don’t always respect the boundaries of species. That’s especially true among bacteria and other microbes, in which genes can be shuttled from one species to another. To understand the evolution of single-celled organisms, scientists are increasingly focusing on individual genes, tracing their journeys through time and among species. The path of their journeys looks more like a web. And since life was almost entirely single-celled for the first two billion years of its history, we must see the opening chapters of our biological history as a tapestry rather than a tree.

THE HUMAN RECIPE

Over the past decade, scientists have sequenced not just the human genome, but the genomes of chimpanzees, monkeys, and many other animals. Now that they can comb through these genetic archives, they are starting to work out how the genomes of our ancestors changed after they branched off from other primates. The work begins with a catalog. Scientists have tallied up genes that were accidentally duplicated in our lineage, for example, so that we now have more copies of them than do other primates. They’ve also identified genes that became pseudogenes. And some genes in humans got their start as noncoding DNA in other primates. Recently Aoife McLysaght of the Smurfit Institute of Genetics at Trinity College Dublin discovered three proteins produced by humans that aren’t found in our closest non-human relatives. McLysaght then discovered that the genes for these three human proteins correspond almost precisely to stretches of noncoding DNA in the other species. It appears that mutations transformed these pieces of genetic material into genes capable of making proteins.

chimpanzees

Geneticists have begun to ferret out the genetic differences that have accumulated in our lineage since it diverged from the lineage of chimpanzees, our closest living relatives.EnlargePhoto credit: © Gary Wales/istockphoto

 

Our genomes are unique in other ways that are subtle yet no less important. While we share just about all our protein-coding genes in common with chimpanzees, the actual sequence of some of them differs slightly. In many cases, those differences are biologically meaningless; both versions of the protein in question work perfectly well. But in some cases, natural selection was at work. Scientists are amassing a growing list of genes in which they find compelling evidence that mutations in our ancestors boosted their reproductive success. Natural selection has also left its mark on noncoding DNA since our ancestors branched off from other primates, too.

We are, of course, more than just a unique catalog of genetic elements. Scientists are only now starting to find the meaning in the bits of DNA unique to our species. In some cases, these differences evolved as a result of the unique kinds of viruses and other pathogens we face. In other cases, these differences emerged as we evolved the secret to human success: our unmatched mental versatility. Scientists are beginning to identify genes involved in language and other uniquely human kinds of behavior that underwent dramatic changes in the past few million years. Today, 150 years after the Origin of Species, we’re just getting to know our evolutionary selves.

EVOLUTIONARY MEDICINE

In 1996, Randolph Nesse, a psychiatrist, and George Williams, an evolutionary biologist, published a book entitled Why We Get Sick. They argued that in order to understand health and disease, scientists had to consider our evolutionary heritage. The book helped inspire a number of scientists—both medical researchers and evolutionary biologists—to establish a new field of inquiry called evolutionary medicine.

H1N1 swine flu

The flu virus forces us through its continual evolution to develop new vaccines each year to combat its novel strains. Here, the new H1N1 swine flu that appeared in the spring of 2009. EnlargePhoto credit: Courtesy CDC

 

In a sense, evolutionary biologists have been investigating medicine for a long time now. In the late 1950s, for example, Williams first began to ponder why we—and other animals—get old. Williams argued that natural selection favors adaptations for reproducing early in life, even if those adaptations have harmful side effects later on. In recent years, evolutionary biologists have joined forces with medical researchers to analyze these ideas together. Many recent studies on the molecular biology of aging support Williams’s basic concepts. Knowing that, in effect, aging is a side effect of a vibrant youth is helping researchers investigate new ways to slow the aging process itself.

Evolution also makes viruses and other pathogens such powerful threats to our survival, even in an age when we can sequence their DNA. That’s because their DNA is a moving target, mutating and hitting upon new solutions to the age-old challenge of turning us into breeding grounds for disease. But tracing the evolution of our microscopic enemies can also reveal their vulnerabilities—the ways in which they can’t evolve effectively. These weak spots are becoming new targets for preventions and treatments. We may not be able to stop evolution, but we can at least learn how to use it to our advantage. [See an interview with swine flu expert Peter Palese (in Editors’ Picks at left).]