Stories tagged DNA sequencing

Feb
08
2010

The Discovery of King Tut: Howard Carter, staging the discovery of King Tut, in 1922.
The Discovery of King Tut: Howard Carter, staging the discovery of King Tut, in 1922.Courtesy Wiki Media Commons
Science Buzz bloggers have been buzzing about this topic for some time, but as the time draws near, I thought I would jump in for those new to Science Buzz. The rapidly expanding field of DNA analysis is now being used to verify the genealogy of the great kings of Egypt. Zahi Hawass, chief of the Supreme Council of Antiquities in Egypt, has announced that on February 17th, 2010 he will be revealing the results of DNA testing on the famous mummy of the boy king, Tutankhamun. DNA testing has already been done on King Amenhotep III (who reigned from approximately 1388 to 1351 BCE) for comparison as he is believed to be either Tut’s father or grandfather. The mummy of Amenhotep’s son, Akhenaten (who could be Tut’s father), has yet to be found. Researchers also plan to test the DNA of two mummified fetuses found in the tomb to determine if they are related to Tut and shed light on whether King Tut’s bride, daughter of Akhenaten, was his full sister or half sister.

Despite the popularity of King Tut and the splendid artifacts found in his tomb, he is actually only a minor figure in the history of Egyptian pharaohs, reigning for a mere 10 years in a time of great unrest. The story of Akhenaten is more interesting. Akhenaten, who ruled from 1352 to 1336 BCE, is famous for changing both religion and artistic style in Egypt, what is now known as the Amarna Period. Akhenaton introduced a new monotheistic cult of worship surrounding the sun disc Aten and excluded all other Egyptian gods from being worshipped in an effort to suppress the powerful priesthood of Amun.

Pharaoh Akhenaten: Classic Amarna Period sculpture of the Pharaoh Akhenaten.
Pharaoh Akhenaten: Classic Amarna Period sculpture of the Pharaoh Akhenaten.Courtesy Hajor and Wiki Media Commons
Artwork during the Amarna Period took on a more naturalistic style and often emphasized affectionate family scenes of the Pharaoh with his wife Nefertiti and their children. Of interest to many art historians is the depiction of Akhenaten himself. He is represented with an accentuated feminine appearance, rounded protruding belly, wide hips, long slender limbs, and a long thin face. Some believe it is a purposeful political depiction stressing his belief in equality of the sexes, some suggest he was a hermaphrodite, and others suggest he had Marfan’s syndrome. People with Marfan’s syndrome are usually very tall with long thin arms and legs, have thin faces, and funnel shaped chests. Unfortunately, until his mummy is located this will remain a mystery.

When Akhenaten died, the priests of Amun regained power, striking Akhenaten’s name from Egyptian records, reversed all of his religious and governmental changes, and returned the capitol to Thebes. His son, Tutankhaten changed his name to Tutankhamun to honor Amun and became the now famous boy king ruling from 1336 to 1327 BCE.

Mr. Hawass has announced plans to test all the royal mummies using their new $5 million DNA lab in the Egyptian museum. However, there is some concern in the scientific field that he will not submit results to labs outside Egypt for independent verification as is common practice in DNA testing. For example, DNA results of Hatshepsut, Egypt’s famous, powerful and only female pharaoh have never been released. Our fascination with the pharaohs is sure to continue for many more centuries.

Jul
24
2007

Squish it down, roll it out, and it becomes a worm: Photo NOAA.
Squish it down, roll it out, and it becomes a worm: Photo NOAA.

When it’s related to jellyfish. In 1851 scientists discovered an odd marine worm called Buddenbrockia. Unlike other worms, it has no internal organs. According to Oxford zoologist Peter Holland, “It has no mouth, no gut, no brain and no nerve cord. It doesn’t have a left or right side or a top or bottom – we can’t even tell which end is the front!”

No one knew where exactly if fit on the evolutionary tree. Until now. Holland studied the creatures DNA and found it is actually a close relative of jellyfish, sea anemones and coral.

Before you shrug your shoulders and say “so what?,” realize that Buddenbrockia is a parasite, and comes from a whole family of parasites. It devastates salmon fisheries, and has been hard to eradicate, since the fish farmers didn’t know what they were up against. Now we do.

Holland also notes that this research was made possible by the Human Genome Project, which decoded all the DNA in the human body. Not that human genes have anything much to do with jellyfish and worms. Rather, the Human Genome Project developed new, powerful ways to quickly study DNA. Those methods are now available to other researchers who could never have developed them on their own. In science, we call this the Trickle Down Effect.

Sep
15
2006

Black cottonwood: Courtesy Oak Point Nursery
Black cottonwood: Courtesy Oak Point Nursery

Ever heard of Populus trichocarpa? It sure is shaking up what researchers understand about plant biology and evolution. That’s right, Populus trichocarpa is a tree, more specifically a black cottonwood.

The black cottonwood is the first tree to have its full DNA code sequenced. Reports state the poplar tree has far less DNA in its cells than humans or other mammals, but twice the number of genes. The poplar has 485 million basepairs! Basepairs are the letters orchestrating a genetic code (A=adenine, T=thymine, C=cytosine, G=guanine). Researchers have found more than 45,000 possible genes (units of hereditary information). To put this number in perspective, humans and other mammals have a little over 20-25,000 genes.

Why is this cool?

Besides figuring out specific questions about botany, having the full DNA sequence of the black cottonwood will also have industrial implications.

The research team discovered 93 genes of the poplar where involved in making cellulose. Cellulose is an organic material found in large quantities on Earth. Cellulose is the primary structural component of green plants. It can be broken down into sugar, fermented into alcohol and distilled to produce fuel-quality ethanol.

Dr. Gerald Tuskan, the lead author of the report in Science, stated, “Biofuels are not only attractive for their potential to cut reliance on oil imports but also their reduced environmental impact.”

Populus trichocarpa identification:

Leaf structure: Alternate, simple, deciduous, ovate-laneolate to deltoid, dark green and silvery white underneath, wavy margins.

Fruit: Releases cottony-tufted seeds
Bark: When young, it is smooth and yellowish tan to gray; later on it turns gray to gray-brown and has deep furrows and flattened ridges.

Form: Tallest broad-leaved tree in the West. Able to grow up to 200 feet tall and 6 feet in diameter.

Found: Flood plains and along river and stream banks. Prefers moist/wet sites.

Keep your eyes open for a black cottonwood tree near you!