Stories tagged DNA testing

Feb
17
2010

Ibex: Capra ibex
Ibex: Capra ibexCourtesy Nino Barbieri
A recent article in the Journal of Archaeological Science reminded me of the importance of the Scientific Method Often we hear new and exciting scientific theories that seem plausible, especially if these ideas are presented in prestigious journals. However, the beauty of the Scientific Method is its verifiability, whether or not the data can be recreated through repetitive testing (If we truly believed everything the first time, our budding young scientists would have nothing to do!)

Michael Campana from the University of Cambridge and colleagues from across the UK and Ireland recently ran a sequence of DNA tests on 18th and 19th century parchments made from animal skins in order to reveal the complexities of ancient parchment analysis. Parchment is one of the most valuable archaeological and historical artifacts that can be used to understand not only language and history, but DNA testing on it can reveal clues to animal population studies, animal husbandry, different historical animal breeds, and provenance (where the animal or skins originated from). In the case of the Dead Sea Scrolls, DNA testing on the parchment could reveal what type of animal was used and possibly where it came from, providing additional data for questions regarding who wrote the scrolls.

Campana and colleagues analyzed both mitochondrial and autosomal genetic data using stable isotope, genetic, phylogenetic and ion beam analysis. All samples were considered to be well preserved and ideal samples for accurate testing. All but one parchment produced multiple DNA sequences that matched several different species including cow, goat, sheep, and even human. In other words, a parchment assumed to be made from one individual of one species, gave conflicting results as more than one species or more than one individual. Of course it can be assumed the parchment was not made of human skin and therefore human genetic data must have came from handling and processing of the parchment, but parchments can also be contaminated in long-term storage or contact with each other. Testing results can also be skewed by glues and inks or other preparatory treatments used to improve the surface. All of these factors need to be considered when testing truly ancient parchment like the Dead Sea Scrolls.

Previous DNA test results from 2001 and 1996 on the Dead Sea Scrolls produced results pointing to a single species, either ibex (Capra ibex) or domestic goat. While these results may indeed be correct, the likelihood that the results were so exact, when testing such as Campana's and colleagues on better preserved and more recent parchment were so complex, questions the accuracy of the earlier DNA testing. Of course we must not forget, precious artifacts like the Dead Sea Scrolls can not be needlessly dissected to offer unlimited samples for DNA testing labs. But as, Campana states, “Improving our understanding of parchment's DNA content would allow us to develop a predictive model for sampling of historic manuscripts.”

So the messages for today, bravo for the Scientific Method and go see the Dead Sea Scrolls at the Science Museum! Learn the science, archaeology, history and more that surround these amazing artifacts. Ask questions like: did the scroll writers choose ibex for some scrolls over goat because they thought these documents were so special or was ibex as readily available as any other animal species? Did the handling of the scrolls by shepherds who supposedly found them contaminate the actual scroll DNA with sheep, human or goat DNA? What can DNA testing tell us about other ancient artifacts? As long as there are unanswered questions, no matter how small, there will be a need for scientific investigation; which is good news for our future scientists!

Feb
16
2010

What's wrong with Tut?: CT scans and DNA tests conducted over the past two years have uncovered several major problems that contributed to King Tut's death: malaria, broken leg, a club foot and restricted blood flow to Tut's left foot.
What's wrong with Tut?: CT scans and DNA tests conducted over the past two years have uncovered several major problems that contributed to King Tut's death: malaria, broken leg, a club foot and restricted blood flow to Tut's left foot.Courtesy Sanandreas
Being a boy king of Egypt had it’s share of downs along with all the gold and glitter.

CT scans and DNA testing conducted on the mummy to King Tutankhamun (King Tut for short) show that the boy pharaoh was suffering from several medical problems at the time of his death at age 19.

The contemporary medical testing shows that Tut had a cleft palate and a club foot and was suffering from malaria and a broken leg at the time that he died some 3,300 years ago. The results were announced today and will be published Wednesday in the Journal of the American Medical Association.

Medical experts have also been able to untangle the web of intrigue as to who Tut’s parents were, sort of. DNA shows that Tut is the son of the previous pharaoh, Akhenaten, and his likely mother is an unidentified sister of Akhenaten. In total, 16 mummies underwent CT scanning to get a better picture of who Tut was and what the times were like when he was alive.

The 21st Century testing was able to answer more than half of Tut’s paternity questions by identifying his father. And while we know that Akhenaten’s sister was Tut’s mother, her mummified remains confirm Tut’s DNA, her identity is still unknown. It was not uncommon in New Kingdom Egypt for pharaohs to marry to their sisters.

The findings put to bed once and for all long-held speculation that Tut was murdered. That idea was fueled by a hole in his skull, but a 2005 scan of Tut’s mummy showed that hole was made as part of the mummification process.

The majesty that we associated with Tut based on the ornate furnishings found in his burial chamber may be a far cry from what life was like for the finals days of the boy king. The medical testing shows that Tut was a sickly teen who was done in by complications from the broken leg and malaria in his brain.

On top of that, Tut had a club foot that likely required him to use a cane. In fact, 130 canes or walking sticks have been found among his burial goods, with some of the canes showing wear and tear. Tut also suffered from Kohler's disease in which lack of blood flow was slowly destroying the bones of his left foot.

Another theory cleared up through the medical tests: Tut did not suffer from any medical conditions that would have given him female body characteristics or misshapen bones.

Want to learn more? Here’s a Q&A with Egyptologist Zahi Hawass, secretary general of Egypt's Supreme Council of Antiquities, about the new Tut findings.

And here is even more in-depth coverage from National Geographic.

Bummed out that Tut was so sickly and need a pick-me-up? Do you really need a shot of Steve Martin's "King Tut" song right now? Enjoy (with a special guest appearance by Fonzie [aka Henry Winkler]). Maybe Steve needs to add a new verse to include all this new medical information.