According to a group of geneticists in Switzerland from iGENEA, the DNA genealogy center, as many as half of all European men and 70 percent of British men share the same DNA as the Egyptian Pharaoh Tutankhamun, or King Tut.

Tuthankamen's famous burial mask, on display in the Egyptian Museum in Cairo. Source: wikipedia

For a film created for the Discovery Channel, scientists worked to reconstruct the DNA of the young male King, his father Akhenaten and his grandfather Amenhotep III. They discovered that King Tut had a DNA profile that belongs to a group called haplogroup R1b1a2. This group can be found in over 50 percent of European men and shows the researchers that there is a common ancestor.

This genetic profile group is also found in 70 percent of Spanish males and 60 percent of French males however, it is only present in less than one percent of men in modern-day Egyptian men.

The R1b1a2 DNA haplogroup is believed to have originated in the Black Sea region some 9500 years ago and spread to Europe with the spread of agriculture in 7000BC. Researchers are unsure as to how and when the group first came to Egypt. They believe the reasoning the R1b1a2 haplogroup is rarely found in modern-day Egypt is due partially to European immigration throughout the last 2000 years.

iGENEA plans to continue to search for more DNA lineage and are looking to discover King Tut’s closest living relatives. They announced this week that they are selling a DNA service for between 139 and 399 euros and they will test the DNA of those people who are interested in seeing how related to King Tut they may be. This offer, according to Roman Scholz who is the director of iGENEA, has already gained a lot of interest.

© 2010 PhysOrg.com

When an animal gets too hot or too cold, or feels pangs of hunger or thirst, it tends to relocate – to where it's cooler or hotter, or to the nearest place where food or water can be found. But what about vegetative life? What can a plant do under similar circumstances?

Plants can't change the climate and they can't uproot themselves to move to a more favorable spot. Yet they do respond successfully to changes in environmental conditions in diverse ways, many of which involve modifications of the way they grow and develop.

Plant biologists at Cold Spring Harbor Laboratory (CSHL) have now discovered at the genetic level how one species of grass plant responds to the challenge to growth posed by shade. Central to this work is the team's identification of the role played by a gene called grassy tillers1, or gt1, whose expression, they confirmed, is controlled by light signaling.

The discovery of gt1's role is full of implication, for it occurs in maize, one of the world's most important food crops, and the genetic trick it performs, which results in changing the plant's shape, suggests how maize's ancestor in the grass family was domesticated by people in Mexico and Central America thousands of years ago. The discovery also suggests a present-day strategy for improving yield in switchgrass, a biofuel source.

In maize – or corn, as it is commonly referred to in North America – it has long been known at the level of effects, but not causes, how an unimpressive grass plant called teosinte was improved upon genetically through trial and error to become a prime source of food for the human race. As anyone who has seen a corn field knows, modern maize plants grow in close proximity, in long rows, and tend to produce robust, branchless stalks which yield one or two large ears apiece.

"The domestication of maize from its wild ancestor teosinte resulted in a striking modification of the plant's architecture, and this fact provided a starting point for our work," says CSHL Professor David Jackson, who led the research team which also included scientists from Cornell University; the University of Wisconsin, Madison; North Carolina State University; the University of California, San Diego and Pioneer Hi-Bred. The team's findings appear today online ahead of print in Proceedings of the National Academy of Sciences.

One can plainly see that maize plants produce very few lateral branches at their base. The sparseness of tillers, as these branches are called by plant biologists, is the first clue: plants with many lateral branches don't tend to grow well in close proximity, for their branches and leaves tend to throw any close neighbors into shade, thus limiting access to sunlight, their common prime energy source. By severely limiting its lateral branching, maize is able to redirect its energy to the primary shoot, which grows taller and escapes the shade.

"It is actually human selection that has done this," explains Jackson. "Although maize plants produce tiller buds, the nascent branches fail to grow out, which results in the plant's familiar dominant central stalk." The team knew that maize plants in which gt1 is mutated generate several tillers and additional ear branches; this suggested that gt1 expression is normally associated with the suppression of tiller growth. This was confirmed in tests in which gt1 expression was measured in plants grown in the laboratory equivalent of shade.

Another maize gene called teosinte branched1, or tb1, is also known to regulate tiller bud growth and lateral branching in maize, and to be active in response to internal signals indicating the presence of shade. The next question was whether the two genes act in a common pathway, or separately. The expression of each was measured when the other was experimentally inactivated. "We found that gt1 doesn't get activated unless tb1 is active; but that tb1 can act without gt1," says Jackson. "Taken together, our experiments indicated that the two genes are indeed part of a common pathway, in which gt1 is downstream of tb1 – it is not expressed until after tb1 is expressed."

Knowing that ancestral teosinte is a highly branched and tillered plant, the team tested the hypothesis that it was the gt1 gene that was specifically (if unwittingly) selected by ancient agriculturalists in their trial-and-error attempts to domesticate a wild grass to produce a new source of food. By sequencing gt1 from diverse lines of modern maize and wild teosinte, "we obtained significant evidence that gt1 was selected during domestication," according to Jackson.

"Tillering is an important trait in the grass family, and by modifying tiller production agriculturalists have increased yield in grasses such as maize and rice. Understanding the molecular mechanisms behind that modification may now provide us with a means to increase biomass production in switchgrass or other potential biofuel crops," Jackson adds.

Provided by Cold Spring Harbor Laboratory (web)

DNA, a molecule famous for storing the genetic blueprints for all living things, can do other things as well. In a new paper, researchers at the National Institute of Standards and Technology (NIST) describe how tailored single strands of DNA can be used to purify the highly desired "armchair" form of carbon nanotubes. Armchair-form single wall carbon nanotubes are needed to make "quantum wires" for low-loss, long distance electricity transmission and wiring.

Wrapped up in their work: this molecular model shows a single-strand DNA molecule (yellow ribbon) coiled around an "armchair" carbon nanotube. Credit: Roxbury, Jagota/NIST

Single-wall carbon nanotubes are usually about a nanometer in diameter, but they can be millions of nanometers in length. It's as if you took a one-atom-thick sheet of carbon atoms, arranged in a hexagonal pattern, and curled it into a cylinder, like rolling up a piece of chicken wire. If you've tried the latter, you know that there are many possibilities, depending on how carefully you match up the edges, from neat, perfectly matched rows of hexagons ringing the cylinder, to rows that wrap in spirals at various angles—"chiralities" in chemist-speak.

Chirality plays an important role in nanotube properties. Most behave like semiconductors, but a few are metals. One special chiral form—the so-called "armchair carbon nanotube" - behaves like a pure metal and is the ideal quantum wire, according to NIST researcher Xiaomin Tu.

Armchair carbon nanotubes could revolutionize electric power systems, large and small, Tu says. Wires made from them are predicted to conduct electricity 10 times better than copper, with far less loss, at a sixth the weight. But researchers face two obstacles: producing totally pure starting samples of armchair nanotubes, and "cloning" them for mass production. The first challenge, as the authors note, has been "an elusive goal."

Separating one particular chirality of nanotube from all others starts with coating them to get them to disperse in solution, as, left to themselves, they'll clump together in a dark mass. A variety of materials have been used as dispersants, including polymers, proteins and DNA. The NIST trick is to select a DNA strand that has a particular affinity for the desired type of nanotube. In earlier work,*** team leader Ming Zheng and colleagues demonstrated DNA strands that could select for one of the semiconductor forms of carbon nanotubes, an easier target. In this new paper, the group describes how they methodically stepped through simple mutations of the semiconductor-friendly DNA to "evolve" a pattern that preferred the metallic armchair nanotubes instead.

"We believe that what happens is that, with the right nanotube, the DNA wraps helically around the tube," explains Constantine Khripin, "and the DNA nucleotide bases can connect with each other in a way similar to how they bond in double-stranded DNA." According to Zheng, "The DNA forms this tight barrel around the nanotube. I love this idea because it's kind of a lock and key. The armchair nanotube is a key that fits inside this DNA structure—you have this kind of molecular recognition."

Once the target nanotubes are enveloped with the DNA, standard chemistry techniques such as chromatography can be used to separate them from the mix with high efficiency.

"Now that we have these pure nanotube samples," says team member Angela Hight Walker, "we can probe the underlying physics of these materials to further understand their unique properties. As an example, some optical features once thought to be indicative of metallic carbon nanotubes are not present in these armchair samples."

More information: J. Am. Chem. Soc., Article ASAP DOI: 10.1021/ja205407q

Provided by National Institute of Standards and Technology (NIST)