Mitochondrial Eve and you

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We’re all brothers and sisters under the skin — or at least distant cousins. According to the popular Single-Origin Hypothesis (the “Out of Africa” theory), the human race originated in eastern Africa something like 100,000-200,000 years ago. The alternative Multiregional Hypothesis (which seems less likely to me, but what do I know) says that Homo sapiens evolved independently in several places, but even then there were Homo habilis ancestors that evolved in Africa — the question is really which populations should and should not count as Homo sapiens.

That means that we share common ancestors. And no, you needn’t be one of the three million Irish descended from Niall of the Nine Hostages, or the sixteen million people worldwide descended from Genghis Khan. If you go back far enough, you’ll eventually hit the human race’s most recent common ancestor, some lucky breeder with billions of living descendants — possibly as late as the first or second millenium BCE. We can also imagine tracing back to Mitochondrial Eve and Y-chromosomal Adam — our most recent common ancestors through purely matrilineal and patrilineal lines, respectively. (Adam and Eve didn’t know each other; he lived 60,000-90,000 years ago, while she was perhaps 150,000 years ago.) The point is, if you follow your family tree backwards, it keeps branching into more and more ancestors, and eventually all of our individual trees get mixed together. So, for example, Bill O’Reilly and Michael Moore are distantly related, although the family reunions are likely a bit awkward.

An obvious question is: how did we get from there to here? How did human DNA mix and match, spread out through various locales and ethnicities, and focus together to create that pinnacle of biological achievement: you? Well, a new project from National Geographic, IBM, Spencer Wells, and the Waitt Foundation aims to find out: the Genographic Project (hat tip to Maria). They are collecting DNA samples from all over the world, and using genetic markers characteristic of certain populations to infer how humans migrated across the globe, cheerfully (or not so cheerfully, often enough) reproducing along the way.

Best of all: you can participate! Sadly, you have to pay ($100) to join the project, rather than receiving recompense for your services; but it’s pretty cool. You get a kit that allows you to take a sample of your own DNA and send it in for analysis. The results won’t tell you about your immediate family, but they’ll reveal the geographical origins of your deeper ancestry. C’mon, you want to know where your haplogroup originated, don’t you? And we need to hurry, before the intimate (as it were) interconnectivity of the global village scrambles our genetic markers once and for all.

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Perspective

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Political humor is always a tricky business; taking a strong stand tends to annoy more than half of your potential audience rather than make them laugh, while wishy-washy moderation just isn’t that funny. This post at Joe’s Dartblog pops open the hood on an editorial cartoon and looks inside, showing something we don’t usually get to see: three cartoons about a single topic, by the same artist, taking three different ideological perspectives (left, moderate, right). Even though I love political humor when it’s insightful and agrees with my predelictions, this exercise actually highlights the rhetorical limitations of the medium. A joke isn’t an argument, and the techniques of humor can be much more directly employed to bolster opinions that people already have than to make them see things in a new way. (Via the Volokh Conspiracy.)

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The future of the universe

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This month’s provocative results on the acceleration of the universe raise an interesting issue: what can we say about our universe’s ultimate fate? In the old days (like, when I was in grad school) we were told a story that was simple, compelling, and wrong. It went like this: matter acts to slow down the expansion of the universe, and also to give it spatial curvature. If there is enough matter, space will be positively curved (like a sphere) and will eventually collapse into a Big Crunch. If there is little matter, space will be negatively curved (like a saddle) and expand forever. And if the matter content is just right, space will be flat and will just barely expand forever, slowing down all the while.

Fate of the universe This story is wrong in a couple of important ways. First and foremost, the assumption that the only important component of the universe is “matter” (or radiation, for that matter) is unduly restrictive. Now that we think that there is dark energy, the simple relation between spatial curvature and the ultimate fate of the universe is completely out the window. We can have positively curved universes that expand forever, negatively curved ones that recollapse, or what have you. (See my little article on the cosmological constant.) To determine the ultimate fate of the universe, you need to know both how much dark energy there is, and how it changes with time. (Mark has also written about this with Dragan Huterer and Glenn Starkman.)

If we take current observations at face value, and make the economical assumption that the dark energy is strictly constant in density, all indications are that the universe is going to expand forever, never to recollapse. If any of your friends go on a trip that extends beyond the Hubble radius (about ten billion light-years), kiss them goodbye, because they won’t ever be able to return — the space in between you and them will expand so quickly that they couldn’t get back to you, even if they were moving at the speed of light. Meanwhile, stars will die out and eventually collapse to black holes. The black holes will ultimately evaporate, leaving nothing in the universe but an increasingly dilute and cold gas of particles. A desolate, quiet, and lonely universe.

However, if the dark energy density actually increases with time, as it does with phantom energy, a completely new possibility presents itself: not a Big Crunch, but a Big Rip. Explored by McInnes and by Robert Caldwell, Marc Kamionkowski, and Nevin Weinberg, the Big Rip happens when the universe isn’t just accelerating, but super-accelerating — i.e., the rate of acceleration is perpetually increasing. If that happens, all hell breaks loose. The super-accelerated expansion of spacetime exerts a stretching force on all the galaxies, stars, and atoms in the universe. As it increases in strength, every bound structure in the universe is ultimately ripped apart. Eventually we hit a singularity, but a very different one than in the Big Crunch picture: rather than being squashed together, matter is torn to bits and scattered to infinity in a finite amount of time. Some observations, including the new gamma-ray-burst results, show a tiny preference for an increasing dark energy density; but given the implications of such a result, they are far from meeting the standard for convincing anyone that we’ve confidently measured any evolution of the dark energy at all.

So, it sounds like we’d like to know whether this Big Rip thing is going to happen, right? Yes, but there’s bad news: we don’t know if we’re headed for a Big Rip, and no set of cosmological observations will ever tell us. The point is, observations of the past and present are never by themselves sufficient to predict the future. That can only be done within the framework of a theory in which we have confidence. We can say that the universe will hit a Big Rip in so-and-so many years if the dark energy is increasing in density at a certain rate and we are sure that it will continue to increase at that rate. But how can we ever be sure of what the dark energy will do twenty trillion years from now? Only by actually understanding the nature of the dark energy can we extrapolate from present behavior to the distant future. In fact, it’s perfectly straightforward (and arguably more natural) for a phase of super-accelerated expansion to last for a while, before settling down to a more gently accerated phase, avoiding the Big Rip entirely. Truth is, we just don’t know. This is one of those problems that ineluctably depends on progress in both observation and theory.

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Crank up your word processors

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I’m sure we have a slew of budding Pynchons and Stoppards out there in the CV audience. Here’s your chance to break into the big time: the Second Annual Seed Magazine Fiction Supplement.

In the June/July issue Seed will publish its Second Annual Fiction Supplement. We are not looking for traditional Sci-Fi — we are looking for fiction that reflects the significant role science plays in our culture; fiction that uncovers the rich narratives in science; and fiction wherein scientists are fallible and human. We are looking for Science-In-Fiction, Fictional Science and Scientific Fiction — in the tradition of Andrea Barrett, Richard Powers, Margaret Atwood and Alan Lightman, writing that brings new meaning to our understanding of Science Fiction.

Scientists are fallible and human? Sorry, can’t help them there. Remember, if anyone who reads this post goes off and writes a story that gets into the magazine, we want to hear about it.

Update: Apparently we’re talking about an entire genre of fiction here — LabLit. (Via grrlscientist.)

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Extremophilia

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D. RadioduransThe Astronomy Picture of the Day from Sunday was a cool one — a nutrient agar plate of Deinococcus radiodurans, a/k/a “Conan the Bacterium.” (Photo: M. Daly, Uniformed Services University of the Health Sciences.) D. rad is quite the remarkable little microbe — it’s an extremophile, an organism that thrives in conditions that you and I would deem overly harsh. (And no, not the internet.) It even has a listing in the Guinness Book of World Records under “World’s Toughest Bacterium.”

D. rad is able to survive in vacuum and through extremes of temperature as well as dehydration, but its special ability is to shrug off large amounts of radiation: a dosage 3,000 times what would kill a strapping young human. Now, you may perhaps wonder why the Intelligent Designer would bother to equip a certain unicellular organism with such an impressive, but not manifestly adaptive, kind of superpower. It could be that radiation tolerance was quite useful in the environment of the very young Earth, but biologists are also thinking that the radiation resistance may come along with resistance to dehydration (which is something that obviously is useful) — radiation and dehydration seem to cause similar types of DNA damage, and D. rad has a remarkable ability to keep its DNA in good working order. It carries along several copies of its genome, stacked on top of each other, ready to step in at the first sign of damage. It’s like towing an entire repair shop behind your car at all times.

Which means, of course, that we meddling humans want to put it to work. D. rad has already been genetically engineered to clean up spills of toxic mercury, which can be highly radioactive. And now, NASA is exploring the possibility of recruiting the plucky bacteria into the astronaut corps. They are imagining adapting D. rad to help with a variety of tasks that humans might face on a trip to Mars — synthesizing drugs, recycling wastes, producing food, all the way up to terraforming the planet. If I were in charge of this project, I would tread pretty lightly here. These are some tough bacteria — I wouldn’t be surprised if they’re just biding their time until we can fly them to Mars, at which point they’ll rise up and take over both planets.

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Get out the vote!

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Sir Isaac Newton may have written the greatest physics work of all time, but he shouldn’t rest easy — he has heavy competition for being the greatest experimenter. Chad Orzel at Uncertain Principles aims to find out. He’s assembled an impressive list of nominees for the greatest physics experiment ever (and is drumming up interest in the greatest in other fields). Contenders include such household names as Galileo, Roemer, Faraday, Cavendish, Michelson and Morley, Hertz, Rutherford, Hubble, Mossbauer, and Aspect, not to mention Newton himself. Greedy bastard. Be sure to go vote.

On the opposite side of the practicality/speculation scale, Christine Dantas has the somewhat more modest goal of finding the Best Quantum Gravity Paper of 2005. Help out, she needs both nominees and votes. Of course what we think is the best paper now might not be what we remember a hundred years later.

A final way to have your own bit of vox populi be heard is to visit Wampum and vote for the Koufax awards (previously mentioned here). You’ll have to keep checking in, as posts where you can actually vote are gradually being assembled; so far we’ve seen

If I’m good I’ll keep a list here. We’ve been nominated in a few categories, including Best New Blog; I have high hopes for a respectable third-place showing in the Best Expert Blog category behind Pharyngula and Informed Comment.

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Word crisis

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Forget about Peak Oil, here’s the real looming crisis: we’re running out of new words. Do you realize how hard it is, in our hyperactive age, to come up with a word that hasn’t already been invented for some purpose or another? Surely we’ve all had the experience of mistyping a word into Google and nevertheless hitting a handful of results. So as a little experiment, I made up some strings of letters that sounded like they could be words, checked in the dictionary that none of them actually exists as a conventional English word, and asked Google to go look for them. Here’s how many hits I got.

  • antrith (865)
  • splicky (230)
  • queigh (43)
  • nurdle (885)
  • tobnet (53)

“Splicky” is a pretty sweet-sounding word, actually; I’ll have to start dropping it into conversation. Admittedly, most non-words appear on Google as abbreviations or computer terms or simple nonsense, and furthermore it’s not that hard to invent random strings that don’t get any hits. Still, I’m worried. If Shakespeare were alive today, I’m pretty sure he’d feel that Google was cramping his style, coinage-wise.

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Sanctity of Human Life Day

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Today is the 33rd anniversary of Roe v. Wade. It is also Blog for Choice Day. It has also, by way of a sharp stick in the eye to those who believe women should be the ones to choose to have abortions or not, been declared National Sanctity of Human Life Day by President Bush. This is from the President’s proclamation.

National Sanctity of Human Life Day, 2006
A Proclamation by the President of the United States of America

Our Nation was founded on the belief that every human being has rights, dignity, and value. On National Sanctity of Human Life Day, we underscore our commitment to building a culture of life where all individuals are welcomed in life and protected in law.

America is making great strides in our efforts to protect human life. One of my first actions as President was to sign an order banning the use of taxpayer money on programs that promote abortion overseas. Over the past 5 years, I also have been proud to sign into law the Born-Alive Infants Protection Act, the Unborn Victims of Violence Act, and a ban on partial-birth abortion. In addition, my Administration continues to fund abstinence and adoption programs and numerous faith-based and community initiatives that support these efforts.

When we seek to advance science and improve our lives, we must always preserve human dignity and remember that human life is a gift from our Creator. We must not sanction the creation of life only to destroy it. America must pursue the tremendous possibilities of medicine and research and at the same time remain an ethical and compassionate society.

It’s funny, but try as I might, I can’t “remember” that my life is a gift from a mythical Creator. And I wish the President would stop trying to enshrine his personal beliefs as national policy.

But the Culture of Life does crack me up. In this week’s New York Review, Garry Wills reviews the latest book by Jimmy Carter, on the hijacking of moral values by conservatives.

Yet the anti-life movement that calls itself pro-life protects ignorance by opposing family planning, sex education, and informed use of contraceptives, tactics that not only increase the likelihood of abortion but tragedies like AIDS and other sexually transmitted diseases. The rigid system of the “pro-life” movement makes poverty harsher as well, with low minimum wages, opposition to maternity leaves, and lack of health services and insurance. In combination, these policies make ideal conditions for promoting abortion, as one can see from the contrast with countries that do have sex education and medical insurance. Carter writes:

Canadian and European young people are about equally active sexually, but, deprived of proper sex education, American girls are five times as likely to have a baby as French girls, seven times as likely to have an abortion, and seventy times as likely to have gonorrhea as girls in the Netherlands. Also, the incidence of HIV/ AIDS among American teenagers is five times that of the same age group in Germany…. It has long been known that there are fewer abortions in nations where prospective mothers have access to contraceptives, the assurance that they and their babies will have good health care, and at least enough income to meet their basic needs.

The “culture of life” idea traces its origin to the Catholic doctrine that life is a seamless garment, to be respected from conception to grave — but its American incarnation has dropped some of the inconvenient bits, like opposition to the death penalty. As Governor of Texas, Bush presided over a record spree of executions, while ridiculing death row inmates’ pleas for clemency. Wills continues:

Capital punishment is also a pro-death program. It does not protect life. It aligns us with authoritarian regimes: “Ninety percent of all known executions are carried out in just four countries: China, Iran, Saudi Arabia—and the United States” (emphasis added). Execution does not deter, as many studies have proved. In states that abolished it, Carter writes, capital crimes did not increase:

The homicide rate is at least five times greater in the United States than in any European country, none of which authorizes the death penalty. The Southern states carry out over 80 percent of the executions but have a higher murder rate than any other region. Texas has by far the most executions, but its homicide rate is twice that of Wisconsin, the first state to abolish the death penalty. It is not a matter of geography or ethnicity, as is indicated by similar and adjacent states: the number of capital crimes is higher, respectively, in South Dakota, Connecticut, and Virginia (all with the death sentence) than in the adjacent states of North Dakota, Massachusetts, and West Virginia (without the death penalty).

How can a loving religion or a just state support such a culture of death? Only a self-righteous and punitive fundamentalism, not an ethos of the gospels, can explain this.

On its anniversary, Roe v. Wade is threatened as never before. Perhaps it will have to be eviscerated beyond recognition before the American public will make an effort to preserve abortion rights.

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You would constantly be depressed and tired

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From the BBC, via 3 Quarks Daily, a survey of British schoolchildren on their views about scientists.

The Science Learning Centre in London asked 11,000 pupils for their views on science and scientists. Around 70% of the 11-15 year olds questioned said they did not picture scientists as “normal young and attractive men and women”. The research examined why numbers of science exam entries are declining. They found around 80% of pupils thought scientists did “very important work” and 70% thought they worked “creatively and imaginatively”. Only 40% said they agreed that scientists did “boring and repetitive work”.

Over three quarters of the respondents thought scientists were “really brainy people”. The research is being undertaken as part of Einstein Year. Among those who said they would not like to be scientists, reasons included: “Because you would constantly be depressed and tired and not have time for family”, and “because they all wear big glasses and white coats and I am female”.

We obviously need to start posting more pictures of ourselves in our cool black leather lab coats. This white-lab-coat stereotype cannot stand.

Update: In the comments, Anna points to a fun site at Fermilab, describing the impressions that kids have of scientists both before and after visiting the lab. These drawings are by Amy.

Impressions of scientists

The pictures are great, but the written descriptions are even better. Here is Beth, before::

The scientist has big square-shaped glasses and a big geeky nose with brown hair and blue eyes. I see a scientist working in a lab with a white lab coat . . . holding a beaker filled with solutions only he knows. Scientists are very interesting people who can figure out things we don’t even know exist.

And after visiting:

My picture of a scientist is completely different than what it used to be! The scientist I saw doesn’t wear a lab coat. . . . The scientists used good vocabulary and spoke like they knew what they were talking about.

Note “spoke like,” not simply “knew what they were talking about.” That Beth is a smart cookie.

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Could have predicted this

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Man, I go away for a couple of days and all my co-bloggers choose to take a siesta. I’m going to have to give them a good talking-to, I tell you.

Now I’m stuck in Philadelphia for one night more than planned, due to an unforeseen outbreak of weather back in Chicago. The City of Brotherly Love has greatly come up in the world since I grew up in the suburbs a couple of decades ago — the Rittenhouse Square neighborhood, where I’m staying, is a really lively and engaging downtown environment.

Nothing of substance to report, so I’ll point you to this takedown of astrology by Phil Plait of Bad Astronomy fame, which is worthy of some contemplation. We all know that astrology is nonsense, but it’s worth the exercise to try to explain to people who aren’t well-versed in science why we know that astrology can’t work even without doing elaborate double-blind tests. Phil’s argument is the same one that I’ve given before: we really do know something about the forces of nature, and there is absolutely no room to fit paranormal phenomena into what we know. There’s much we don’t know, and much we do; sometimes we even have a pretty good idea of where the boundary is.

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