# Random Samples

Science  24 Jun 2005:
Vol. 308, Issue 5730, pp. 1864
1. # Panoramic Mosaic

Tousled gladiator may have been German. A 2000-year-old mosaic uncovered at the ruins of the ancient Roman city of Leptis Magna on the coast of Libya is wowing archaeologists and art historians. The gory depiction of a nearby amphitheater includes a highly detailed profile of a gladiator with his vanquished foe and a spectacular chariot race crash.

The 9-meter-long mosaic, described this week in the British archaeological journal Minerva, was discovered in 2002 by a team led by Marliese Wendowski, an archaeologist at the University of Hamburg, Germany. “From the start, we knew we had something special because it was so large,” says Wendowski. The team members kept the find a secret while they excavated it and transferred it to the nearby Leptis Magna Museum.

“What's extraordinary is how depth was created with foreshortening,” a very painterly technique, says Minerva editor Mark Merrony. The artist “must have been working from a drawing,” he adds.

The mosaic is offering fresh clues for historians. “This was likely an eyewitness account commissioned by a very rich local patron,” says Merrony, and it shows how interconnected the Roman empire was at the time. Men are shown wrestling with bears and deer, the first evidence that European animals were imported to Africa for sport. But that's not all. “Judging by his face and hair, I think the gladiator was a German barbarian,” says archaeologist Helmut Ziegert, also at the University of Hamburg. That might explain why no name was inscribed, an honor typically bestowed on respected gladiators.

2. # Chimera on a Bike?

A high-profile sports blood-doping case has taken a bizarre twist, with the accused cyclist arguing that testing positive for two distinct types of blood indicates he is a chimera.

Last September, Olympian Tyler Hamilton, 34, of Boulder, Colorado, was accused of taking a blood transfusion to boost his performance after a newly developed test showed he had two different types of red blood cells. Hamilton denied the charge, and with the help of geneticist David Housman of the Massachusetts Institute of Technology in Cambridge, he has been arguing that he might be a chimera: an organism with a mix of genetically distinct cells.

Human chimeras are not all that rare, Housman told a board arbitrating the case in March. Mothers and fetuses often exchange blood-producing stem cells, and fetuses can also get foreign cells from sharing the womb with a “vanishing twin,” he said. But the arbitrators didn't bite, voting 2 to 1 to uphold a 2-year suspension and stating that blood doping was “the only reasonable conclusion.” Encouraged by the split decision, however, Hamilton is again appealing, this time to a sport arbitration court in Switzerland. Although other blood samples showed that his minority cell population decreased over several months, Housman says that is consistent with chimerism.

Mother-fetus chimerism is unlikely to produce foreign cells at the levels found in Hamilton's blood—about 2%—says geneticist Wendy Robinson of the University of British Columbia in Vancouver, Canada. But Housman predicts that more athletes who are actually chimeras will show up as suspected blood dopers. And, wrote Hamilton this month in his online journal, “If we've accomplished nothing else in this case, we have put a spotlight on the vanishing twin phenomenon.”

3. # Early Tree

Fossil palm. Paleontologists this week got their best look yet at one of the world's first trees, a palmlike growth that flourished in a tropical environment in the middle Devonian Period, about 380 million years ago.

Only fragments were previously known of the tree, called Pseudosporochnus. But last summer, staff from the New York State Museum in Albany came across a 3-meter-long specimen in a gravel quarry near Conesville, New York—the first time the foliage has been found attached to the trunk. It is well preserved with a crown made up of frondlike branches. Although no roots are in evidence, “it gives us the first clear impression of what this tree looked like,” says William Stein of the State University at Binghamton, New York, who is studying the fossil. “What really strikes me is how modern it is,” says Stein, noting its leaflike branches. (Modern leaves had not yet evolved.) The fossil was described at the North American Paleontology Conference in Halifax, Nova Scotia, by New York state paleontologist Ed Landing.

4. # Jobs

Forward into the past. In more ways than one, molecular evolutionist Alan Cooper is going back to his roots. Leading the new Australian Centre for Ancient DNA at the University of Adelaide will be a homecoming of sorts for the New Zealander, former head of the Ancient Biomolecules Centre at the University of Oxford, U.K. The new post also gives him a better shot at obtaining intact DNA from the puny human species Homo floresiensis, who lived in neighboring Indonesia about 18,000 years ago. “It's going to be bloody difficult with that heat,” he says. “However, the importance of the material is huge, and we'll throw every trick in the book at it.”

6. # Tapping Into New Talent

Mark Lewney, a U.K. patent examiner, knows how to make science sing. This month, Lewney (left) won a U.K. science communication talent contest modeled after American Idol in which more than 300 contestants riffed on scientific topics to a panel of academics and journalists. During one of the rounds of FameLab, Lewney explained “why spaceships on the telly are rubbish” (for one, they wouldn't make any noise in space), and described Orion, an interplanetary ship driven by atomic bombs that was proposed in the 1950s.

For his final performance, Lewney took up an electric guitar to explain how the harmonics of its strings create distinctive distorted sounds. “Ignoring the judges' advice about how to be a calm, authoritative TV presenter, I plugged my electric guitar into my amp and turned it up loud,” Lewney says. Science writer Simon Singh, one of the judges, found the Orion presentation especially impressive: “He used only a frying pan as a prop and still got the audience excited.”

Lewney earned nearly $3700 and a few television spots as well. Runners-up David Booth, an evolutionary biologist from Belfast, and Matt Wilkinson, a zoologist from Cambridge, each won about$1400.