Using hair from a 20,000 year-old mammoth, Penn State researchers have successfully deciphered more than half of the extinct mammal’s DNA. The feat was made possible by new “high throughput” DNA sequencing technology, which is able to generate massive amounts of DNA sequence in very short order.

Not surprisingly, the mammoth’s DNA is amazingly similar to the current-day African elephant. In fact, the close evolutionary relationship (~99.6% DNA identity) has led some to speculate that it might be possible to “fill in the gaps” of the missing mammoth DNA with elephant DNA. Then you’d be on your way to re-creating a complete set of genetic instructions for a mammoth. Get the genes into an egg, figure out how to trick the egg into thinking it’s been fertilized, and…

Well, not so fast. As pointed out in the journal Nature, the idea of bringing a mammoth’s DNA sequence “to life” faces enormous technical hurdles. Not least among these is that we do not yet have the technology to synthesize and assemble mammalian chromosome-length stretches of DNA (tens to hundreds of millions of letters). Currently, the record for a synthetic chromosome is approximately half a million letters. There’s also the issue of getting the DNA appropriately packaged into chromosomes, getting the chromosomes, undamaged, inside an egg cell nucleus, figuring out how to activate the egg cell nucleus, etc. Let’s just say that the mammoth won’t be brought back from extinction any time soon.

But do stay tuned for news regarding the world’s first synthetic bacterium. The J. Craig Venter Institute announced last summer that they had synthesized the Mycoplasma genitalium genome and were working on getting the synthetic genome working inside of a bacterial cell.

Here’s a link to Penn State’s Woolly Mammoth Genome Project site.

Original Article

How’d you like to go to Mars? Well, if you’re in grade K-12, you have the opportunity to pick the name for NASA’s next Mars rover. The winner will visit NASA’s Jet Propulsion Laboratory in California for a tour and a chance to “sign” the rover headed to Mars.

NASA’s Mars exploration website is here, including videos from the recent Phoenix lander mission and a history of all Mars missions.

Original Article

In a strange twist on the “veggie burger” concept, University of Hawaii researchers have concluded that more than 90% of a typical fast food hamburger originally comes from corn. Not corn ground up and pressed into a patty, but corn eaten by cattle and metabolized to muscle, then eventually processed to hamburger. 

Of concern is that this work highlights the degree to which the American cattle industry depends on corn as feed. Corn is widely viewed as an environmentally “costly” crop, requiring lots of fertilizer, soil-damaging cultivation, and gas-burning heavy machinery. Grass-fed beef is viewed as not only friendlier to the environment, but also healthier. The tradeoff is that grass-fed cattle require much more land for grazing and grow more slowly. For a $0.99 hamburger, grass-fed beef just isn’t a reality.

Original Article

Two groups of astronomers reported this week that, for the first time, they had directly laid eyes on planets outside our solar system. The two groups reported a total of four new “exoplanets:” three are orbiting a star 128 light years away, and another orbits a star 25 light years away. Given that 1 light year is approximately 5.9 trillion miles, these planets won’t be visited any time soon.

Planets orbiting distant stars are difficult to see because the parent star’s bright light overwhelms any reflected light that the planet may direct towards earth.  Although more than 300 exoplanets have been identified, their existence to date has been inferred by indirect means – for example, by observing a planet’s effect on other celestial objects (stars, dust rings), or their ability to block light as they pass in front of a star.

Being able to directly image other planets will allow astronomers to determine their chemical composition and perhaps infer whether they could support life. For the current discovery, none of the four are believed to have life-friendly conditions.

A photo of the three-planet system can be found at the Lawrence Livermore National Laboratory website.

Original Article

In an effort to better understand the genetics of cancer, researchers at the Washington University School of Medicine in St. Louis have completely sequenced the genome of a woman fatally afflicted with leukemia, a cancer of the blood. This was an important step because the exact genetic errors that lead to many cancers are not known.

To determine which genes might be involved in this particular form of leukemia, researchers performed a conceptually simple – but technically very challenging – experiment: compare the DNA sequence from the woman’s leukemic bone marrow cells to DNA sequence from her own normal skin cells, and look for differences. Ideally, both cell types should have basically identical DNA sequences (all cells contain the same master set of DNA “instructions”). Differences arise, though, because cells acquire DNA mutations (errors) during one’s lifetime. Some of these may contribute to disease.

After reading the 3 billion letters of her tumor and skin genomes many times over (~140 billion total letters of DNA sequenced!), they found 10 gene mutations in her marrow cells that likely led to the disease. Eight of these genes had not previously been linked to leukemia.

Exactly how these genes might contribute to leukemia remains to be determined. But researchers now have a new set of targets that may help in the search for better diagnostics and ultimately cures. Sequencing many more genomes of patients with leukemia will be necessary for the full genetic picture to emerge, but this is certainly a great start.

All of this work has been made possible by the completion of the Human Genome Project in 2003, and by amazing technical advances in our ability to sequence DNA.

More about the idea of “personalized medicine” – using genetic information to help determine the best course of health care – can be found in Dr. Rex Chisholm’s recent SiS article. You can also listen to an audio interview with Dr. Timothy Ley, who led the study, courtesy of NPR’s Science Friday.

Original Article

Though not widely reported in the popular media, a shockingly high number of animal and plant species are at risk for extinction – on the order of a third of all amphibians and more than 10 percent of all birds. In this article, Stuart Pimm, noted environmental biologist, discusses his work to preserve the diversity of life on earth.  He notes that 1% of ALL species on earth may be gone in 10 years, unless immediate action is taken.

Of note, Pimm visited Northwestern in 2005 as part of a global warming and biodiversity public education event.  His talk is definitely worth a look (link to video).

Original Article