You Don't Know the Half of It
Some people are just born to inspire a Law & Order episode. Such is the case with a young pair of twins recently profiled in the journals Nature and Human Genetics. These siblings—one male, one hermaphroditic—are the first known instance of semi-identical twins, apparently conceived when two different sperm fertilized one egg. The twins share all maternal genetic material but only about half of paternal alleles. Both twins are chimeric, expressing some cells with genetic material from one sperm (XX) and some cells with genetic material from the other (XY). Scientists already knew that two sperm could fertilize a single egg, but researchers had never before seen such an embryo survive. The twins are now toddlers, and doctors say they're progressing well, but when one of them commits a murder and leaves cells more easily identified with the other at the scene of the crime, remember, you heard it here first.
Advertisement
Doubting Thomas's Lineage
Thanks to modern genetics, we have good reason to believe that Thomas Jefferson fathered at least one child with his slave, Sally Hemings. Nearly a decade ago, researchers matched TJ's rare Y chromosome to Ms. Hemings's descendants'. Now, the same group of researchers has jumped into the president's genes once again, looking to trace his geographic origins. Jefferson's Y chromosome belongs to a rare group called K2, and the researchers say this haplotype is most common in East African and the Middle East. Could our beloved third president have come from the same place as (gasp!) Saddam Hussein or (gasp!) Jesus? Or perhaps Jefferson was a (more gasps!) Sephardic Jew? Fear not, xenophobes. The researchers tested 85 British men with the Jefferson surname and found that two had the same K2 Y chromosome as the president. They say their results are "consistent with Jefferson's patrilineage belonging to an ancient and rare indigenous European type." Well, now we can all sleep at night, secure in our history of dead white male presidents.
Running Out of Air
Within seconds, Sunita Williams will beat everyone else running the Boston Marathon. It's not tough to do when you're orbiting Earth at nearly 28,000 kilometers per hour. But US astronaut Williams will jog the whole 26.2 miles on the ISS treadmill, circling Earth at least twice in the process. In January 2006, Williams was the 74th woman to finish the Houston Marathon (3:30:31), thereby qualifying for the Boston Marathon. She may be out of town, but Williams refuses to forfeit her entry. The astronaut said she is running to motivate children to be physically fit. During her stint on the International Space Station, Williams has been running at least four times a week, completing two shorter runs and two longer runs. The marathon isn't the only way Williams is demonstrating her superior endurance: It is unclear when a shuttle will be able to pick her up from the station, so Williams may break the record for longest stay in space by a US astronaut.