January 15, 2006
Food
Generation Pad Thai
By JENNIFER STEINHAUER
The owner of the Gucci handbag plunked it down at the Fairway cash register, next to three expensive cheeses, a large filet mignon, two packages of Cocoa Puffs Milk ‘n Cereal Bars and an eight-pack of apple juice boxes, and impatiently awaited her tally.
If we can infer that the apple juice was not meant as a chaser for her English farmstead cheese, may we then stop to ponder why she would foist such foodstuffs on her offspring? Or is it that American children have somehow conspired to turn their otherwise reasonable parents into weak-willed rulers of their collective roosts, tricked into believing that it is acceptable to ask a dinner-party host carving a roast for a corn-syrup-packed protein alternative. Truly, a chicken/nugget conundrum.
The same parents who micromanage every other aspect of their children’s lives - puzzle tutoring for 4-year-olds, clarinet lessons, baby yoga - seem to stop the mini-me’ing at the lunch box. The evidence surrounds us. Syrupy shots of glucose masquerading as yogurt. Premade peanut-butter-and-jelly sandwiches. (I long to have been in that marketing meeting: “Working parents have no time to hoist a butter knife!”) An abomination called string cheese.
Skip your starchy e-mail about food snobbery: even those parents who torture others with cellphone conversations plotting a reservation at the new Batali venture serve Gummi Bears as a soccer snack. Do not be fooled!
So what would Daniel Boulud do? Foie-gras-stuffed chicken fingers?
I polled several chefs with young children to see what they fed them and found serious challenges to the notion that small people simply will not brook fresh vegetables, texture or spice. They serve their children pad Thai, which blends pungent seasonings like fish sauce and tamarind with noodles, eggs and peanuts.
“I look in people’s fridges and it appalls me,” said Hugo Matheson, a chef at the Kitchen in Boulder, Colo. “The demographic around here doesn’t have financial issues, but they still buy prepackaged lasagna from Whole Foods when all the kid really needs to eat is half a chicken breast.”
The fact that chefs’ kids eat better than yours or mine isn’t surprising. They often bring the little ones to work, where they eat tiny plates of duck confit (“They lap it up,” said Matheson of his nearly 3-year-old twins) or buckwheat pasta (the 2-year-old and 4-year-old children of Scott Dolich of Park Kitchen in Portland, Ore., request it). They also have rules at home:
1. Make your children eat at the table from a very young age. Jody Adams, the chef at Rialto in Cambridge, Mass., said that her children - Oliver and Roxanne - never had highchairs. “It was really hard, because 2-year-olds throw food. But I saw the benefit in treating the dinner table as something that was important and that everyone had to participate in.”
2. Make them eat what you do, even if you have to purée it. “If we ate butternut squash and carrots, so did they,” Matheson said, “and sometimes with fish. I just really thinned it with cooking water.” Grant Achatz, the chef and owner of Alinea in Chicago, treated his 4-year-old to a 10-course dinner. “He didn’t finish everything, but he tried every course, which included white truffles, crab, bison,” he said. Do not feel compelled to top this.
3. Pack lunches fashioned from leftovers. “If we go for Thai food,” said Naomi Hebberoy, a chef and owner of the Gotham Building Tavern in Portland, Ore., her daughter, August, “takes pad Thai the next day.”
4. Eschew Baggies filled with Goldfish. (Car rides are exempt.) “If kids are hungry, they’re going to eat,” Dolich said. “If you fill them up on Bugles, they won’t.”
5. Buy them the most expensive chocolate you can afford. Who craves Ho Hos when they’ve had Scharffen Berger? I do. But I wasn’t raised on the good stuff.
Lest you think this is some culinary tomfoolery, these are the food ways our forefathers hewed to. “Historically, there was no such thing as children’s food,” said Andrew F. Smith, who teaches culinary history at the New School in New York. “Babies would eat what adults ate, chopped up, until Gerber created baby food in 1927.” “Children’s meals” didn’t exist until the McDonald’s Happy Meal came along in the late 1970’s, Smith said, and only when snack-food producers concluded that their real market was children did they start sponsoring events and advertising in the 1950’s.
A caveat: Even chefs’ kids eat boxed macaroni and cheese (albeit Annie’s, the organic kind). Feel free to wolf down wooden spoonfuls of it as you make it, too.
Pad Thai
8 ounces rice noodles
1 tablespoon tamarind paste
1 ½ tablespoons fish sauce
1 ½ tablespoons sugar
1 tablespoon lime juice
4 cups broccoli florets
1 carrot, thinly sliced
½ cup canola oil
2 teaspoons minced garlic
1 teaspoon minced ginger
16 large shrimp, peeled and deveined
2 large eggs, lightly beaten
3 scallions, thinly sliced
1 cup bean sprouts
1/3 cup chopped salted peanuts
3 tablespoons chopped cilantro
1 lime, cut into wedges
Sesame seeds
Red pepper flakes (optional).
1. Place the noodles in a bowl and cover with cold water. Let sit for 1 hour.
Meanwhile, in a small bowl, whisk together the tamarind paste, fish sauce, sugar, lime juice and ¼ cup water; set aside. Lightly steam the broccoli and carrot; set aside.
2. Drain the noodles. Set a wok over high heat for 1 minute, then add the oil and heat until almost smoking. Add the garlic and ginger; sauté for 30 seconds. Add the shrimp and sauté until almost cooked through, 2 to 3 minutes. Transfer to a plate.
3. Add the noodles and stir-fry for 1 minute. Pour in three-quarters of the tamarind sauce and toss to coat the noodles. Add more sauce if needed. Cook until the noodles are al dente, then push them to one side of the wok and scramble the eggs in the remaining space. Add the shrimp, broccoli, carrot, scallions, bean sprouts and half the peanuts. Toss to mix. Divide among 4 plates and garnish with the remaining peanuts, the cilantro, lime wedges, sesame seeds and (for brave children) red pepper flakes. Serves 2 adults and 2 children. Adapted from Naomi Hebberoy of Gotham Building Tavern.
Oliver’s Chicken Stew
1 3 ½ - to 4-pound chicken, rinsed
8 cups chicken stock
Salt and freshly ground black pepper
5 medium carrots, thickly sliced
4 medium leeks, tender white part only, thickly sliced
4 celery stalks, thickly sliced
4 cloves garlic, smashed
1 teaspoon chopped thyme
1 bay leaf
3 sprigs flat-leaf parsley
½ cup stellini (tiny star pasta)
3 tablespoons unsalted butter
1 tablespoon lemon juice
1 tablespoon chopped tarragon
¼ cup chopped flat-leaf parsley
6 slices toasted Italian bread
¼ cup extra-virgin olive oil
½ cup grated Parmesan cheese.
1. Place the chicken in a 6-quart pot breast side down. Add the stock, lightly seasoned with salt and pepper, and bring to a boil, skimming often. Add the carrots, leeks, celery, garlic, thyme, bay leaf and parsley and simmer. After 15 minutes, flip the chicken and cook for 25 minutes more. Remove the chicken and let cool.
2. Strain the vegetables, discarding the bay leaf and parsley. Return the stock to the pot; simmer until reduced by half. Pull the chicken meat off the bones. Add the pasta to the stock and cook for 3 minutes, then whisk in the butter, lemon juice, tarragon and parsley. Add the chicken and vegetables; heat through.
3. To serve, place a piece of toast in the bottom of each of 6 bowls, then drizzle with olive oil and sprinkle with Parmesan. Top with stew. Serves 6. Adapted from “In the Hands of a Chef,” by Jody Adams and Ken Rivard.
Monday, January 23, 2006
Crystal meth replacing home-cooked
Link
January 23, 2006
As States Curb Homemade Meth, a More Potent Variety Emerges
By KATE ZERNIKE
DES MOINES, Jan. 18 - In the seven months since Iowa passed a law restricting the sale of cold medicines used to make methamphetamine, seizures of homemade methamphetamine laboratories have dropped to just 20 a month from 120. People once terrified about the neighbor's house blowing up now walk up to the state's drug policy director, Marvin Van Haaften, at his local Wal-Mart to thank him for making them safer.
But Mr. Van Haaften, like officials in other states with similar restrictions, is now worried about a new problem: the drop in home-cooked methamphetamine has been met by a new flood of crystal methamphetamine coming largely from Mexico.
Sometimes called ice, crystal methamphetamine is far purer, and therefore even more highly addictive, than powdered home-cooked methamphetamine, a change that health officials say has led to greater risk of overdose. And because crystal methamphetamine costs more, the police say thefts are increasing, as people who once cooked at home now have to buy it.
The University of Iowa Burn Center, which in 2004 spent $2.8 million treating people whose skin had been scorched off by the toxic chemicals used to make methamphetamine at home, says it now sees hardly any cases of that sort. Drug treatment centers, on the other hand, say they are treating just as many or more methamphetamine addicts.
And although child welfare officials say they are removing fewer children from homes where parents are cooking the drug, the number of children being removed from homes where parents are using it has more than made up the difference.
"It's killing us, this Mexican ice," said Mr. Van Haaften, a former sheriff. "I'm not sure we can control it as well as we can the meth labs in your community."
The influx of the more potent drug shows the fierce hold of methamphetamine, which has devastated many towns once far removed from violent crime or drugs. As Congress prepares to restrict the sale of pseudoephedrine, the cold medicine ingredient that is used to make methamphetamine, officials here and in other states that have recently imposed similar restrictions caution that they fall far short of a solution.
"You can't legislate away demand," said Betty Oldenkamp, secretary of human services in South Dakota, where the governor this month proposed tightening a law that last year restricted customers to two packs of pseudoephedrine per store. "The law enforcement aspects are tremendously important, but we also have to do something to address the demand."
Here, officials boast that their law restricting pseudoephedrine, which took effect in May, has been faster than any other state's in reducing methamphetamine laboratories. Still, when Mr. Van Haaften, director of the Governor's Office of Drug Control Policy, surveyed the local police, 74 percent said that the law had not changed demand, and 61 percent said supply had remained steady or increased.
In a survey of treatment professionals, 92 percent said they had seen as many or more methamphetamine addicts; the state treated 6,000 in 2005 and expects to treat more than 7,000 this year, based on current trends. Some health officials said abuse among women, typically the biggest users of methamphetamine, was rising particularly fast.
While seizures of powdered methamphetamine declined to 4,572 in 2005 from 6,488 in 2001, seizures of crystal methamphetamine increased, to 2,025 from one.
Federal drug agents tend to describe ice as methamphetamine that is at least 90 percent pure. Officials here say much of their crystal methamphetamine is less pure - "dirty ice," they call it. But either is far more potent than homemade powdered methamphetamine; a "good cook" yields a drug that is about 42 percent pure, but around 25 percent is more common. And in the first four months after the law took effect here, average purity went to 80 percent from 47 percent.
Other states have seen the same.
"The Mexican drug cartels were right there to feed that demand," said Tom Cunningham, the drug task force coordinator for the district attorneys council for Oklahoma, the first state to put pseudoephedrine behind pharmacy counters, in 2004. "They have always supplied marijuana, cocaine, and heroin. When we took away the local meth lab, they simply added methamphetamine to the truck."
A methamphetamine cook could make an ounce for $50 on a stovetop or in a lab in a car; that same amount now costs $800 to $1,500 on the street, the police say.
"Our burglaries have just skyrocketed," said Jerry Furness, who represents Buchanan County, 150 miles northeast of Des Moines, on the Iowa drug task force. "The state asks how the decrease in meth labs has reduced danger to citizens, and it has, as far as potential explosions. But we've had a lot of burglaries where the occupants are home at the time, and that's probably more of a risk. So it's kind of evening out."
When the state surveyed the children in state protection in southeastern Iowa four months after the law took effect, it found that 49 percent were taken from parents who had been using methamphetamine, the same percentage as two years earlier, even as police said they were removing fewer children from homes with laboratories.
Some law enforcement officials say that addicts may find the crystal form more desirable. "If they don't have to mess with precursor chemicals, it's actually a bit easier on them, and safer," said Kevin Glaser, a drug task force supervisor for the state highway patrol in Missouri, which last year led the nation in methamphetamine lab seizures.
But the switch has also increased the risks. "People are overdosing; they're not expecting it to do this much," said Darcy Jensen, director of Prairie View Prevention Services in South Dakota. "They don't realize that that fourth of a gram they're used to using is double or triple in potency."
Federal officials say there are 1.4 million methamphetamine addicts in the United States, concentrated in the West, where the drug began to take hold in the late 1980's, and the Midwest and South, where it moved in the mid- and late 1990's.
Drug enforcement officials have always said that 80 percent of the nation's supply comes from so-called super labs, those able to make 10 pounds or more. But in some counties here, officials say that all the methamphetamine came from mom-and-pop labs that made the drug by cooking pseudoephedrine with toxic farm and household chemicals.
Law enforcement focused on the laboratories because they were so destructive: the police found children who had drunk lye thinking it was water, or went without food as parents went through the long binge-and-sleep cycles of using. Laboratories in homes, motels, abandoned farm buildings or cars frequently exploded, or dumped their toxic chemicals into drains or soil. Small police departments spent much of their time attending to contaminated sites.
More than 30 states have restricted pseudoephedrine in some way. Nine have put it behind pharmacy counters, and Oregon now requires a prescription to obtain it.
Addicts and cookers have proved to be skilled at getting around the restrictions; as one state imposes a law, bordering states see an increase in laboratories. Oklahoma recently linked its pharmacies by a computer database to track sales after discovering that cooks were going county-to-county buying from several pharmacies a day.
Iowa's law passed unanimously. As in other states, officials say the number of laboratories had already begun to decline, most likely because cooks feared they would be caught because there was so much public attention on the problem.
The law resulted in a decline of at least 80 percent. Police found 138 laboratories from June to December, down from 673 for the same period the year before. The state had hit a high of 1,500 lab busts in 2004, but with the law, had 731 for 2005, and expects just 257 this year. Law enforcement says the costs of policing and cleaning up labs will drop to $528,000 next year from $2.6 million in 2004.
But here and in many of the states with recent pseudoephedrine restrictions, frustration with the stubborn rate of addiction has moved the discussion from enforcement to treatment and demand reduction.
That discussion, officials say, will be much tougher.
After listening to Mr. Van Haaften's report on the effects of the law this week, State Representative Clel Baudler, a former state trooper who now heads the public safety committee for the Iowa General Assembly, charged his committee to come back to the next meeting with strategies to reduce demand.
"My fear is, when I ask what they think we should do, they'll say 'I don't know,' " Mr. Baudler said in an interview afterward. "We've increased penalties, we've increased prison time, we're still not getting in front of it."
Officials say they never advertised the law as one that would reduce methamphetamine addiction. Still, they are surprised at how the drug has hung on.
"Things that are highly destructive, including diseases, tend to be self-limiting," said Arthur Schut, president of the Mid-Eastern Council on Chemical Abuse in Iowa City, and a member of the state's drug policy advisory council. "This has been devastating. It's remarkable how quickly people are damaged by it."
Mr. Van Haaften, too, knows that it was too much to hope that the law would reduce demand. Still, he says, "I had a little hope."
"I knew of the addictive nature, but in my heart, I believed people didn't want to deal with dealers," he said. "They have guns, it's dangerous, if you make your own it's safer. I hoped for a dip, but the availability did not allow that to happen."
January 23, 2006
As States Curb Homemade Meth, a More Potent Variety Emerges
By KATE ZERNIKE
DES MOINES, Jan. 18 - In the seven months since Iowa passed a law restricting the sale of cold medicines used to make methamphetamine, seizures of homemade methamphetamine laboratories have dropped to just 20 a month from 120. People once terrified about the neighbor's house blowing up now walk up to the state's drug policy director, Marvin Van Haaften, at his local Wal-Mart to thank him for making them safer.
But Mr. Van Haaften, like officials in other states with similar restrictions, is now worried about a new problem: the drop in home-cooked methamphetamine has been met by a new flood of crystal methamphetamine coming largely from Mexico.
Sometimes called ice, crystal methamphetamine is far purer, and therefore even more highly addictive, than powdered home-cooked methamphetamine, a change that health officials say has led to greater risk of overdose. And because crystal methamphetamine costs more, the police say thefts are increasing, as people who once cooked at home now have to buy it.
The University of Iowa Burn Center, which in 2004 spent $2.8 million treating people whose skin had been scorched off by the toxic chemicals used to make methamphetamine at home, says it now sees hardly any cases of that sort. Drug treatment centers, on the other hand, say they are treating just as many or more methamphetamine addicts.
And although child welfare officials say they are removing fewer children from homes where parents are cooking the drug, the number of children being removed from homes where parents are using it has more than made up the difference.
"It's killing us, this Mexican ice," said Mr. Van Haaften, a former sheriff. "I'm not sure we can control it as well as we can the meth labs in your community."
The influx of the more potent drug shows the fierce hold of methamphetamine, which has devastated many towns once far removed from violent crime or drugs. As Congress prepares to restrict the sale of pseudoephedrine, the cold medicine ingredient that is used to make methamphetamine, officials here and in other states that have recently imposed similar restrictions caution that they fall far short of a solution.
"You can't legislate away demand," said Betty Oldenkamp, secretary of human services in South Dakota, where the governor this month proposed tightening a law that last year restricted customers to two packs of pseudoephedrine per store. "The law enforcement aspects are tremendously important, but we also have to do something to address the demand."
Here, officials boast that their law restricting pseudoephedrine, which took effect in May, has been faster than any other state's in reducing methamphetamine laboratories. Still, when Mr. Van Haaften, director of the Governor's Office of Drug Control Policy, surveyed the local police, 74 percent said that the law had not changed demand, and 61 percent said supply had remained steady or increased.
In a survey of treatment professionals, 92 percent said they had seen as many or more methamphetamine addicts; the state treated 6,000 in 2005 and expects to treat more than 7,000 this year, based on current trends. Some health officials said abuse among women, typically the biggest users of methamphetamine, was rising particularly fast.
While seizures of powdered methamphetamine declined to 4,572 in 2005 from 6,488 in 2001, seizures of crystal methamphetamine increased, to 2,025 from one.
Federal drug agents tend to describe ice as methamphetamine that is at least 90 percent pure. Officials here say much of their crystal methamphetamine is less pure - "dirty ice," they call it. But either is far more potent than homemade powdered methamphetamine; a "good cook" yields a drug that is about 42 percent pure, but around 25 percent is more common. And in the first four months after the law took effect here, average purity went to 80 percent from 47 percent.
Other states have seen the same.
"The Mexican drug cartels were right there to feed that demand," said Tom Cunningham, the drug task force coordinator for the district attorneys council for Oklahoma, the first state to put pseudoephedrine behind pharmacy counters, in 2004. "They have always supplied marijuana, cocaine, and heroin. When we took away the local meth lab, they simply added methamphetamine to the truck."
A methamphetamine cook could make an ounce for $50 on a stovetop or in a lab in a car; that same amount now costs $800 to $1,500 on the street, the police say.
"Our burglaries have just skyrocketed," said Jerry Furness, who represents Buchanan County, 150 miles northeast of Des Moines, on the Iowa drug task force. "The state asks how the decrease in meth labs has reduced danger to citizens, and it has, as far as potential explosions. But we've had a lot of burglaries where the occupants are home at the time, and that's probably more of a risk. So it's kind of evening out."
When the state surveyed the children in state protection in southeastern Iowa four months after the law took effect, it found that 49 percent were taken from parents who had been using methamphetamine, the same percentage as two years earlier, even as police said they were removing fewer children from homes with laboratories.
Some law enforcement officials say that addicts may find the crystal form more desirable. "If they don't have to mess with precursor chemicals, it's actually a bit easier on them, and safer," said Kevin Glaser, a drug task force supervisor for the state highway patrol in Missouri, which last year led the nation in methamphetamine lab seizures.
But the switch has also increased the risks. "People are overdosing; they're not expecting it to do this much," said Darcy Jensen, director of Prairie View Prevention Services in South Dakota. "They don't realize that that fourth of a gram they're used to using is double or triple in potency."
Federal officials say there are 1.4 million methamphetamine addicts in the United States, concentrated in the West, where the drug began to take hold in the late 1980's, and the Midwest and South, where it moved in the mid- and late 1990's.
Drug enforcement officials have always said that 80 percent of the nation's supply comes from so-called super labs, those able to make 10 pounds or more. But in some counties here, officials say that all the methamphetamine came from mom-and-pop labs that made the drug by cooking pseudoephedrine with toxic farm and household chemicals.
Law enforcement focused on the laboratories because they were so destructive: the police found children who had drunk lye thinking it was water, or went without food as parents went through the long binge-and-sleep cycles of using. Laboratories in homes, motels, abandoned farm buildings or cars frequently exploded, or dumped their toxic chemicals into drains or soil. Small police departments spent much of their time attending to contaminated sites.
More than 30 states have restricted pseudoephedrine in some way. Nine have put it behind pharmacy counters, and Oregon now requires a prescription to obtain it.
Addicts and cookers have proved to be skilled at getting around the restrictions; as one state imposes a law, bordering states see an increase in laboratories. Oklahoma recently linked its pharmacies by a computer database to track sales after discovering that cooks were going county-to-county buying from several pharmacies a day.
Iowa's law passed unanimously. As in other states, officials say the number of laboratories had already begun to decline, most likely because cooks feared they would be caught because there was so much public attention on the problem.
The law resulted in a decline of at least 80 percent. Police found 138 laboratories from June to December, down from 673 for the same period the year before. The state had hit a high of 1,500 lab busts in 2004, but with the law, had 731 for 2005, and expects just 257 this year. Law enforcement says the costs of policing and cleaning up labs will drop to $528,000 next year from $2.6 million in 2004.
But here and in many of the states with recent pseudoephedrine restrictions, frustration with the stubborn rate of addiction has moved the discussion from enforcement to treatment and demand reduction.
That discussion, officials say, will be much tougher.
After listening to Mr. Van Haaften's report on the effects of the law this week, State Representative Clel Baudler, a former state trooper who now heads the public safety committee for the Iowa General Assembly, charged his committee to come back to the next meeting with strategies to reduce demand.
"My fear is, when I ask what they think we should do, they'll say 'I don't know,' " Mr. Baudler said in an interview afterward. "We've increased penalties, we've increased prison time, we're still not getting in front of it."
Officials say they never advertised the law as one that would reduce methamphetamine addiction. Still, they are surprised at how the drug has hung on.
"Things that are highly destructive, including diseases, tend to be self-limiting," said Arthur Schut, president of the Mid-Eastern Council on Chemical Abuse in Iowa City, and a member of the state's drug policy advisory council. "This has been devastating. It's remarkable how quickly people are damaged by it."
Mr. Van Haaften, too, knows that it was too much to hope that the law would reduce demand. Still, he says, "I had a little hope."
"I knew of the addictive nature, but in my heart, I believed people didn't want to deal with dealers," he said. "They have guns, it's dangerous, if you make your own it's safer. I hoped for a dip, but the availability did not allow that to happen."
Thursday, January 05, 2006
Cat Evolution According to DNA
Link
January 6, 2006
DNA Offers New Insight Concerning Cat Evolution
By NICHOLAS WADE
Researchers have gained a major insight into the evolution of cats by showing how they migrated to new continents and developed new species as sea levels rose and fell.
About nine million years ago - two million years after the cat family first appeared in Asia - these successful predators invaded North America by crossing the Beringian land bridge connecting Siberia and Alaska, a team of geneticists writes in the journal Science today.
Later, several American cat lineages returned to Asia. With each migration, evolutionary forces morphed the pantherlike patriarch of all cats into a rainbow of species, from ocelots and lynxes to leopards, lions and the lineage that led to the most successful cat of all, even though it has mostly forsaken its predatory heritage: the cat that has induced people to pay for its board and lodging in return for frugal displays of affection.
This new history of the family, known as Felidae, is based on DNA analyses of the 37 living species performed by Warren E. Johnson and Stephen J. O'Brien of the National Cancer Institute and colleagues elsewhere.
Before DNA, taxonomists had considerable difficulty in classifying the cat family. The fossil record was sparse and many of the skulls lacked distinctiveness. One scheme divided the family into Big Cats and Little Cats. Then, in 1997, Dr. Johnson and Dr. O'Brien said they thought most living cats fell into one of eight lineages, based on the genetic element known as mitochondrial DNA.
Having made further DNA analyses, the researchers have drawn a full family tree that assigns every cat species to one of the lineages. They have also integrated their tree, which is based solely on changes in DNA, with the fossil record. The fossils, which are securely dated, allow dates to be assigned to each fork in the genetic family tree.
Knowing when each species came into existence, the Johnson-O'Brien team has been able to reconstruct a series of at least 10 intercontinental migrations by which cats colonized the world. The cheetah, for instance, now found in Africa, belongs to a lineage that originated in North America and some three million years ago migrated back across the Bering land bridge to Asia and then Africa.
Dr. O'Brien said the cats were very successful predators, second only to humans, and quickly explored new territories as opportunity arose. Sea levels were low from 11 million to 6 million years ago, enabling the first modern cats, in paleontologists' perspective (saber-tooth tigers are ancient cats), to spread from Asia west into Africa, creating the caracal lineage, and east into North America, generating the ocelot, lynx and puma lineages.
The leopard lineage appeared around 6.5 million years ago in Asia. The youngest of the eight lineages, which led eventually to the domestic cat, emerged some 6.2 million years ago in Asia and Africa, either from ancestors that had never left Asia or more probably from North American cats that had trekked back across the Bering land bridge.
Sea levels then rose, confining each cat species to its own continent, but sank again some three million years ago, allowing a second round of cat migrations. It was at this time that the ancestors of the cheetah and the Eurasian lynxes colonized the Old World from the New.
Chris Wozencraft, an authority on the classification of carnivorous mammals, said the new cat family tree generally agreed with one that he had just published in Mammal Species of the World, a standard reference. Dr. Wozencraft, a taxonomist at Bethel College in Indiana, based his classification on fossil and zoological information, as well as on DNA data already published by Dr. O'Brien's laboratory.
Cat fossils are very hard to tell apart, because they differ mostly just in size, and the DNA data emerging over the last decade has helped bring the field from confusion to consensus, Dr. Wozencraft said.
Despite their evolutionary success, most of the large cats are in peril because their broad hunting ranges have brought them into collision with people. "With the exception of the house cat and a few other small cat species, nearly every one of the 37 species is considered endangered or threatened," Dr. Johnson and Dr. O'Brien write in the current Annual Review of Genomics and Human Genetics.
Fewer than 15,000 tigers, cheetahs and snow leopards remain in the wild, they estimate, and pumas and jaguar populations have been reduced to about 50,000 each.
January 6, 2006
DNA Offers New Insight Concerning Cat Evolution
By NICHOLAS WADE
Researchers have gained a major insight into the evolution of cats by showing how they migrated to new continents and developed new species as sea levels rose and fell.
About nine million years ago - two million years after the cat family first appeared in Asia - these successful predators invaded North America by crossing the Beringian land bridge connecting Siberia and Alaska, a team of geneticists writes in the journal Science today.
Later, several American cat lineages returned to Asia. With each migration, evolutionary forces morphed the pantherlike patriarch of all cats into a rainbow of species, from ocelots and lynxes to leopards, lions and the lineage that led to the most successful cat of all, even though it has mostly forsaken its predatory heritage: the cat that has induced people to pay for its board and lodging in return for frugal displays of affection.
This new history of the family, known as Felidae, is based on DNA analyses of the 37 living species performed by Warren E. Johnson and Stephen J. O'Brien of the National Cancer Institute and colleagues elsewhere.
Before DNA, taxonomists had considerable difficulty in classifying the cat family. The fossil record was sparse and many of the skulls lacked distinctiveness. One scheme divided the family into Big Cats and Little Cats. Then, in 1997, Dr. Johnson and Dr. O'Brien said they thought most living cats fell into one of eight lineages, based on the genetic element known as mitochondrial DNA.
Having made further DNA analyses, the researchers have drawn a full family tree that assigns every cat species to one of the lineages. They have also integrated their tree, which is based solely on changes in DNA, with the fossil record. The fossils, which are securely dated, allow dates to be assigned to each fork in the genetic family tree.
Knowing when each species came into existence, the Johnson-O'Brien team has been able to reconstruct a series of at least 10 intercontinental migrations by which cats colonized the world. The cheetah, for instance, now found in Africa, belongs to a lineage that originated in North America and some three million years ago migrated back across the Bering land bridge to Asia and then Africa.
Dr. O'Brien said the cats were very successful predators, second only to humans, and quickly explored new territories as opportunity arose. Sea levels were low from 11 million to 6 million years ago, enabling the first modern cats, in paleontologists' perspective (saber-tooth tigers are ancient cats), to spread from Asia west into Africa, creating the caracal lineage, and east into North America, generating the ocelot, lynx and puma lineages.
The leopard lineage appeared around 6.5 million years ago in Asia. The youngest of the eight lineages, which led eventually to the domestic cat, emerged some 6.2 million years ago in Asia and Africa, either from ancestors that had never left Asia or more probably from North American cats that had trekked back across the Bering land bridge.
Sea levels then rose, confining each cat species to its own continent, but sank again some three million years ago, allowing a second round of cat migrations. It was at this time that the ancestors of the cheetah and the Eurasian lynxes colonized the Old World from the New.
Chris Wozencraft, an authority on the classification of carnivorous mammals, said the new cat family tree generally agreed with one that he had just published in Mammal Species of the World, a standard reference. Dr. Wozencraft, a taxonomist at Bethel College in Indiana, based his classification on fossil and zoological information, as well as on DNA data already published by Dr. O'Brien's laboratory.
Cat fossils are very hard to tell apart, because they differ mostly just in size, and the DNA data emerging over the last decade has helped bring the field from confusion to consensus, Dr. Wozencraft said.
Despite their evolutionary success, most of the large cats are in peril because their broad hunting ranges have brought them into collision with people. "With the exception of the house cat and a few other small cat species, nearly every one of the 37 species is considered endangered or threatened," Dr. Johnson and Dr. O'Brien write in the current Annual Review of Genomics and Human Genetics.
Fewer than 15,000 tigers, cheetahs and snow leopards remain in the wild, they estimate, and pumas and jaguar populations have been reduced to about 50,000 each.
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