The New York Times
, March 23, 2010Link
Somewhere in England, about 600 years ago, an artist sat down and tried to paint an elephant. There was just one problem: he had never seen one.
The artist was illustrating a book known today as the “Bestiary of Anne Walshe,” a guide to animals. To paint an elephant, he could not jet to Kenya to scrutinize one in person. He could not visit the London zoo. He could not watch a David Attenborough DVD or click through a Web gallery of nature photographs. The only clues the artist could have found were in the mix of facts and myths preserved in old books.
There he might read how elephants cannot bend at the knees, or that they have no interest in sex. There were illustrations of elephants in those old books, too, but they were painted by artists who had also never seen one. In the end, the illustrator of the “Bestiary of Anne Walshe” produced a charming mishmash of guesses. His elephant looks like a bull terrier with camel hooves for feet and a vacuum cleaner for a nose.
Artists are still painting things they cannot see in real life. Rather than being separated from their subjects by thousands of miles, though, today’s artists are separated by thousands of years -- even millions of them. Fortunately, they have a lot more scientific information on which to base their images. But they cannot eliminate the gap between reality and image.
Last month, for example, the portrait of a 4,000-year-old man appeared on the cover of Nature. The picture commemorated the sequencing of the complete genome of an ancient resident of Greenland. In a technical tour de force, a team of scientists extracted DNA from tufts of hairs that had been collected in Greenland in 1986 and stored in a Danish museum since. The scientists discovered that the owner of the Greenland genome -- nicknamed Inuk -- was not all that closely related to Native Americans. Instead, his DNA links him to the Chukchi people of Siberia. The new research suggests that Greenland was peopled in a separate wave of migration from Asia.
The scientists then looked at markers for individual genes that previous studies had linked to particular traits. For example, they discovered that Inuk’s blood was A positive. Other gene variants in Inuk’s DNA have been associated with physical appearance. Some are linked with a high body mass index. Others are linked to brown eyes and dark, thick hair. Inuk had a gene variant associated with a slightly shovel-like shape to the upper front teeth. He even had a gene associated with baldness.
The artist Nuka Godtfredsen used these clues to paint Inuk’s portrait. He studied photographs of Chukchi people to give Inuk a face. He also took note of the fact that, despite Inuk’s genetic propensity for baldness, the tufts of his hair were up to eight inches long. As a compromise, he gave Inuk a receding hairline and a mullet.
Mr. Godtfredsen’s picture is plausible, rather than photographic. It’s impossible to pick out an individual from a police lineup based on nothing but a genome. Dark hair, brown eyes and a stocky build could describe thousands of people who live in the Arctic today. It’s also important to bear in mind that genes rarely guarantee any particular traits; instead, they tend to be associated with them. So we can’t know for sure that having a so-called baldness gene meant that Inuk actually ended up bald. It’s certainly possible that he died too soon to find out.
The better the portrait, the easier it is to forget all the complexity to the science behind it. Last October, the paleoartist Jay Matternes offered up a lovely portrait of a 4.4-million-year-old relative of humans, called Ardipithecus ramidus. Mr. Matternes was invited to paint the hominid by its discoverers, a team of American and Ethiopian scientists who had been digging up and analyzing Ardipithecus bones since the early 1990s and were finally ready to publish a detailed description. In Mr. Matternes’s portrait, Ardipithecus is not quite like anything alive today. It has long, apelike hands and feet and a round, apelike face. And yet it stands upright like a human.
Mr. Matternes worked for years with the scientists on his reconstruction of Ardipithecus. First he drew its skeleton. Onto the skeleton he added muscles, and finally skin and hair. Mr. Matternes infused the picture with a deep artistic understanding of anatomy. But it is also a scientific hypothesis.
The scientists maintain that Ardipithecus stood upright, based on the shapes of bones in its feet, legs, pelvis and spine. But those bones were not perfectly preserved, and the scientists couldn’t just snap them together like a Lego set. The pelvis was so fragmented that the scientists had to use a CT scanner to create three-dimensional models of its pieces, which they then analyzed in the virtual space of a computer.
As a result, some other experts are not ready to endorse the vision of Ardipithecus that Mr. Matternes painted. That doesn’t mean Mr. Matternes is deceiving anyone. It just means that we, the viewers, have to bear in mind how scientists reconstruct the past.
Mr. Matternes can only guess at the color of Ardipithecus by looking at living apes. It turns out that much older fossils hold clues to their hues. Last month the journal Science published a watercolor of a 150-million-year-old feathered dinosaur called Anchiornis. (Anchiornis was an ancient relative of living birds.) The painting, by the wildlife artist Michael DiGiorgio, shows the dinosaur with a crown of rufous plumage, a mottled face, a dark gray body and bold white stripes on its wings.
Mr. DiGiorgio based his painting on a new analysis of the fossil of Anchiornis. Along with the dinosaur’s bones, the fossil also preserved feathers across its whole body. And in those feathers are microscopic structures called melanosomes. The size, shape and arrangement of the melanosomes help give color to the feathers of living birds. The new study on Anchiornis marks the first time that scientists were able to use melanosomes to map the colors of a dinosaur’s entire body.
Like Mr. Matternes and Mr. Godtfredsen, Mr. DiGiorgio spent a long time planning his painting. First he sketched out the body of Anchiornis by studying its skeleton. Mr. DiGiorgio, who usually paints birds, was reminded of roadrunners, so he watched videos of the birds to get ideas about the dinosaur’s posture. He and paleontologists traded sketches back and forth for weeks before he was ready to add feathers. But the feathers were not quite like those of any living bird; for one thing, they covered the entire body of Anchiornis, even down to its feet.
As detailed as Mr. DiGiorgio’s painting is, however, it may not tell the whole story of Anchiornis. Melanosomes are not the only structures that give feathers their colors, and so Anchiornis might have had other patterns on its plumage that have been lost to time. At best, Mr. DiGiorgio has given Anchiornis a base coat.
Still, that’s better than no coat at all. And it’s vastly better than one taken from a bestiary’s pages.
Copyright 2010 The New York Times Company. Reprinted with permission.