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Research into Population Genetics
While not exactly a top-selling book, The History and Geography of Human Genes is a remarkable collection of more than 50 years of research in population genetics. It stands as the most extensive survey to date on how humans vary at the level of their genes. The book's firm conclusion: Once the genes for surface features such as skin color and height are discounted, the "races" are remarkably alike under the skin. The variation among individuals is much greater than the differences among groups. In fact, there is no scientific basis for theories advocating the genetic superiority of any one population over another.
The book, however, is much more than an argument against the latest racially biased theory. The prime mover behind the project, Luca Cavalli-Sforza, a Stanford professor, labored with his colleagues for 16 years to create nothing less than the first genetic map of the world. The book features more than 500 maps that show areas of genetic similarity—much as places of equal altitude are shown by the same color on other maps. By measuring how closely current populations are related, the writers trace the routes by which early humans migrated around the earth. Result: the closest thing we have to a global family tree.
The information needed to draw that tree is found in human blood: various proteins that serve as markers to reveal a person's genetic makeup. Using data collected by scientists over decades, the writers assembled profiles of hundreds of thousands of individuals from almost 2,000 groups. And to ensure the populations were "pure", the study was confined to groups that were in their present locations as of 1492, before the first major movements from Europe began—in effect, a genetic photo of the world when Columbus sailed for America.
Collecting blood, particularly from ancient populations in remote areas, was not always easy. Potential donors were often afraid to cooperate, or had religious concerns. On one occasion, when Cavalli-Sforza was taking blood samples from children in a rural region of Africa, he was confronted by an angry farmer waving an axe. Recalls the scientist: "I remember him saying, 'If you take the blood of the children, I'll take yours.' He was worried that we might want to do some magic with the blood."
Despite the difficulties, the scientists made some remarkable discoveries. One of them jumps right off the book's cover: A color map of the world's genetic variation has Africa at one end of the range and Australia at the other. Because Australia's native people and black Africans share such superficial characteristics as skin color and body shape, they were widely assumed to be closely related. But their genes tell a different story. Of all humans, Australians are most distant from the Africans and most closely resemble their neighbors, the southeast Asians. What the eye sees as racial differences—between Europeans and Africans, for example—are mainly a way to adapt to climate as humans move from one continent to another.
The same map, in combination with ancient human bones, confirms that Africa was the birthplace of humanity and thus the starting point of the original human movements. Those findings, plus the great genetic distance between present-day Africans and non-Africans, indicate that the split from the African branch is the oldest on the human family tree.
The genetic maps also shed new light on the origins of populations that have long puzzled scientists. Example: the Khoisan people of southern Africa. Many scientists consider the Khoisan a distinct race of very ancient origin. The unique character of the clicking sounds in their language has persuaded some researchers that the Khoisan people are directly descended from the most primitive human ancestors. But their genes beg to differ. They show that the Khoisan may be a very ancient mix of west Asians and black Africans. A genetic trail visible on the maps shows that the breeding ground for this mixed population probably lies in Ethiopia or the Middle East.
The most distinctive members of the European branch of the human tree are the Basques of France and Spain. They show unusual patterns for several genes, including the highest rate of a rare blood type. Their language is of unknown origin and cannot be placed within any standard classification. And the fact that they live in a region next to famous caves which contain vivid paintings from Europe's early humans, leads Cavalli-Sforza to the following conclusion: "The Basques are extremely likely to be the most direct relatives of the Cro-Magnon people, among the first modem humans in Europe." All Europeans are thought to be a mixed population, with 65% Asian and 35% African genes.
In addition to telling us about our origins, genetic information is also the latest raw material of the medical industry, which hopes to use human DNA to build specialized proteins that may have some value as disease-fighting drugs. Activists for native populations fear that the scientists could exploit these peoples: Genetic material taken from blood samples could be used for commercial purposes without adequate payment made to the groups that provide the DNA.
Cavalli-Sforza stresses that his mission is not just scientific but social as well. The study's ultimate aim, he says, is to "weaken conventional notions of race" that cause racial prejudice. It is a goal that he hopes will be welcomed among native peoples who have long straggled for the same end.
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Propositional Meaning
Propositional meaningis also referred to assentence meaning. To know the meaning of a sentence is to know what the sentence is all about, and what, who, where, when and how are involved. The following sentences differ in their structure, but they share the same propositional content:
Her colleague regard her as being less than bright.
She is regarded as being less than bright by her colleague.
She strikes her colleague as being less than bright.
In other words, the above three sentences can be used to paraphrase each other's propositional meaning, and therefore paraphrasing becomes a very useful device to help us to check our understanding of the propositional content of a sentence.
The Wake-up Call from Stockholm
"These are the last 2o minutes of peace in your life," the Swedish caller told Caltech professor Ahmed Zewail at 5:4o a.m. on October 12.
Soon the world would hear of Zewail's award — the 1999 Nobel Prize in chemistry — and Zewail would hear from the world. Two thousand e-mails would zoom his way within a few days and three phone lines would start ringing with eager requests for interviews from the national and Egyptian press and with congratulations from friends and colleagues. But first, the 53-year-old man would share the news with his family.
He kissed his wife, Dema, and young sons, Nabeel and Hani. His mother, whom Zewail reached in his native Egypt, cried and cried. His daughters, Maha and Amani, "were going crazy on the phone. I couldn't even speak," said Zewail.
"I was disappointed in Nabeel's reaction," he added. "I told him I had won the prize. He said, 'Good.'" But when Zewail asked if he'd tell the kids at school, the six-year-old said, "No. These guys will say 'So what？'" But Nabeel did ask, "Are we going to see the king？"
The Royal Swedish Academy honored Zewail for his groundbreaking work in viewing and studying chemical reactions at the atomic level as they occur. He has shown "that it is possible with rapid laser technique to see how atoms in a molecule move during a chemical reaction."
Zewail had brought the most powerful tools from the field of physics into the chemistry lab to create a revolution, and the field of femto-chemistry was born. It was "a revolution in chemistry and related sciences," the Swedes announced, "since this type of investigation allows us to understand and predict important reactions," to probe nature at its most fundamental level.
Zewail is the 27th Calteeh faculty member or alumnus to receive the Nobel Prize, and the third faculty member to be so honored in this decade.
"In my experience," said Zewail after a tumultuous week, "whenever you cross fields or bring in new ideas and tools, you find what you don't expect. You open new windows."
Zewail's path to the forefront of the international science arena has been elegant and swift, like the atoms he observes performing molecular dances. With a wealth of experience in home chemistry projects as a boy in Egypt, he sailed to the top of his class at Alexandria University. The classical science education he received there prepared him for a promised tenure-track position in the field of his choice: math, physics, chemistry, or geology, but he decided to get his PhD at the University of Pennsylvania — to "see the molecular world of chemistry." He had heard of Caltech, but to this young Egyptian, "institute" sounded less prestigious than "university." As it turned out, Penn provided the "ideal" transition from classical science studies to the postdoctoral work he did at UC Berkeley.
He stayed at Berkeley for postdoctoral work for two reasons: to think more about research rather than about getting a PhD and "the secret reason — I wanted to buy a big American car to take back to Egypt with me." At Berkeley, he published three papers "immediately" and was advised to apply to the top handful of American universities.
"The most important reason why I decided on Caltech was, once the offer was made, I was well received by the staff, administration, and faculty." He also felt he could make his own way specializing in dynamics in a department strong on structure. And the Mediterranean climate didn't hurt. That was 1976.
Zewail was off and running, earning tenure in a year and a half, making full professorship by 1982, seated in the Pauling Chair by 199o. Now with a Nobel Prize under his belt, what's next？ "First of all, I'm not retiring," he said. "And I'm not going to Hollywood."
In the coming years, Zewail looks forward to more breakthroughs. He will remain active in research and in publishing papers, which he considers to be his babies (363 to date). Tracking the progress of two papers within a week of receiving the prize, he reached a surprised editor who said, "You on the phone？ Impossible! I thought you'd be out wining and dining." He will continue to push the envelope of what is possible.
Choose to Be Alone on Purpose
Here we are, all by ourselves, all 22 million of us by recent count, alone in our rooms, some of us liking it that way and some of us not. Some of us divorced, some widowed, some never yet committed.
Loneliness may be a sort of national disease here, and it's more embarrassing for us to admit than any other sin. On the other hand, to be alone on purpose, having rejected company rather than been cast out by it, is one characteristic of an American hero. The solitary hunter or explorer needs no one as they venture out among the deer and wolves to tame the great wild areas. Thoreau, alone in his cabin on the pond, his back deliberately turned to the town. Now, that's character for you.
Inspiration in solitude is a major commodity for poets and philosophers. They're all for it. They all speak highly of themselves for seeking it out, at least for an hour or even two before they hurry home for tea.
Consider Dorothy Wordsworth, for instance, helping her brother William put on his coat, finding his notebook and pencil for him, and waving as he sets forth into the early spring sunlight to look at flowers all by himself. "How graceful, how benign, is solitude," he wrote.
No doubt about it, solitude is improved by being voluntary.
Look at Milton's daughters arranging his cushions and blankets before they silently creep away, so he can create poetry. Then, rather than trouble to put it in his own handwriting, he calls the girls to come back and write it down while he dictates.
You may have noticed that most of these artistic types went outdoors to be alone. The indoors was full of loved ones keeping the kettle warm till they came home.
The American high priest of solitude was Thoreau. We admire him, not for his self-reliance, but because he was all by himself out there at Walden Pond, and he wanted to be—all alone in the woods.
Actually, he lived a mile, or 20 minutes' walk, from his nearest neighbor; half a mile from the railroad; three hundred yards from a busy road. He had company in and out of the hut all day, asking him how he could possibly be so noble. Apparently the main point of his nobility was that he had neither wife nor servants, used his own axe to chop his own wood, and washed his own cups and saucers. I don't know who did his laundry; he doesn't say, but he certainly doesn't mention doing his own, either. Listen to him: "I never found the companion that was so companionable as solitude."
Thoreau had his own self-importance for company. Perhaps there's a message here: The larger the ego, the less the need for other egos around. The more modest and humble we feel, the more we suffer from solitude, feeling ourselves inadequate company.
If you live with other people, their temporary absence can be refreshing. Solitude will end on Thursday. If today I use a singular personal pronoun to refer to myself, next week I will use the plural form. While the others are absent you can stretch out your soul until it fills up the whole room, and use your freedom, coming and going as you please without apology, staying up late to read, soaking in the bath, eating a whole pint of ice cream at one sitting, moving at your own pace. Those absent will be back. Their waterproof winter coats are in the closet and the dog keeps watching for them at the window. But when you live alone, the temporary absence of your friends and acquaintances leaves a vacuum; they may never come back.
The condition of loneliness rises and falls, but the need to talk goes on forever. It's more basic than needing to listen. Oh, we all have friends we can tell important things to, people we can call to say we lost our job or fell on a slippery floor and broke our arm. It's the daily succession of small complaints and observations and opinions that backs up and chokes us. We can't really call a friend to say we got a parcel from our sister, or it's getting dark earlier now, or we don't trust that new Supreme Court justice.
Scientific surveys show that we who live alone talk at length to ourselves and our pets and the television. We ask the cat whether we should wear the blue suit or the yellow dress. We ask the parrot if we should prepare steak, or noodles, for dinner. We argue with ourselves over who is the greater sportsman: that figure skater or this skier. There's nothing wrong with this. It's good for us, and a lot less embarrassing than the woman in front of us in line at the market who's telling the cashier that her niece Melissa may be coming to visit on Saturday, and Melissa is very fond of hot chocolate, which is why she bought the powdered hot chocolate mix, though she never drinks it herself.
It's important to stay rational.
It's important to stop waiting and settle down and make ourselves comfortable, at least temporarily, and find some grace and pleasure in our condition, not like a self-centered British poet but like a patient princess sealed up in a tower, waiting for the happy ending to our fairy tale.
After all, here we are. It may not be where we expected to be, but for the time being we might as well call it home. Anyway, there is no place like home.
Roommate Conflicts
Identical twins Katie and Sarah Monahan arrived at Pennsylvania's Gettysburg College last year determined to strike out on independent paths. Although the 18-year-old sisters had requested rooms in different dorms, the housing office placed them on the eighth floor of the same building, across the hall from each other. While Katie got along with her roommate, Sarah was miserable. She and her roommate silently warred over matters ranging from when the lights should be turned off to how the furniture should be arranged. Finally, they divided the room in two and gave up on oral communication, communicating primarily through short notes.
During this time, Sarah kept running across the hall to seek comfort from Katie. Before long, the two wanted to live together again. Sarah's roommate eventually agreed to move out. "From the first night we lived together again, we felt so comfortable," says Sarah. "We felt like we were back home."
Sarah's ability to solve her dilemma by rooming with her identical twin is unusual, but the conflict she faced is not. Despite extensive efforts by many schools to make good roommate matches, unsatisfactory outcomes are common. One roommate is always cold, while the other never wants to turn up the furnace, even though the thermometer says it's minus five outside. One person likes quiet, while the other person spends two hours a day practicing the trumpet, or turns up his sound system to the point where the whole room vibrates. One eats only organically produced vegetables and believes all living things are holy, even ants and mosquitoes, while the other likes wearing fur and enjoys cutting up frogs in biology class.
When personalities don't mix, the excitement of being away at college can quickly grow stale. Moreover, roommates can affect each other's psychological health. A recent study reports that depression in college roommates is often passed from one person to another.
Learning to tolerate a stranger's habits may teach undergraduates flexibility and the art of compromise, but the learning process is often painful. Julie Noel, a 21-year-old senior, recalls that she and her freshman year roommate didn't communicate and were uncomfortable throughout the year. "I kept playing the same disk in my CD player for a whole day once just to test her because she was so timid, " says Noel. "It took her until dinner time to finally change it." Although they didn't saw the room in half, near year's end, the two did end up in a screaming fight. "Looking back, ! wish I had talked to her more about how I was feeling," says Noel.
Most roommate conflicts spring from such small, irritating differences rather than from grand disputes over abstract philosophical principles. "It's the specifics that tear roommates apart," says the assistant director of residential programs at a university in Ohio.
In extreme cases, roommate conflict can lead to serious violence, as it did at Harvard last spring: One student killed her roommate before committing suicide. Many schools have started conflict resolution programs to calm tensions that otherwise can build up like a volcano preparing to explode, ultimately resulting in physical violence. Some colleges have resorted to "roommate contracts" that all new students fill out and sign after attending a seminar on roommate relations. Students detail behavioral guidelines for their room, including acceptable hours for study and sleep, a policy for use of each other's possessions and how messages will be handled. Although the contracts are not binding and will never go to a jury, copies are given to the floor's residential adviser in case conflicts later arise. "The contract gives us permission to talk about issues which students forget or are afraid to talk about," says the director of residential programs.
Some schools try to head off feuding before it begins by using computerized matching, a process that nevertheless remains more of a guessing game than a science. Students are put together on the basis of their responses to housing form questions about smoking tolerance, preferred hours of study and sleep, and self-described tendencies toward tidiness or disorder. Parents sometimes weaken the process by taking the forms and filling in false and wishful data about their children's habits, especially on the smoking question. The matching process is also complicated by a philosophical debate among housing managers concerning the flavor of university life: "Do you put together people who are similar—or different, so they can learn about each other？" A cartoon sums up the way many students feel the process works: Surrounded by a mass of papers, a housing worker picks up two selection forms and exclaims, "Likes chess, likes football; they're perfect together!"
Alan Sussman, a second-year student, says, "I think they must have known each of our personalities and picked the opposite," he recalls. While Sussman was neat and serious about studying, his roommate was messy and liked to party into the early hours of the morning. "I would come into the room and find him pawing through my desk, looking for postage for a letter. Another time, I arrived to find him chewing on the last of a batch of chocolate chip cookies my mother had sent me. People in the hall were putting up bets as to when we were going to start slapping each other around, " he says. Against all odds, the two ended up being friends. Says Sussman: "We taught each other a lot—but I would never do it again."
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