micro_life_mars_000812 Part 2 of a 4-Part Series
Mars, 2012: A lean landing craft touches down on
Mars, at a site judged to have the best chances for finding some trace of water. Guided by scientists on Earth, the robot works its way into a crevasse that looks like it might once have hosted an active hot spring. The landing craft begins to sample dirt and scratch rocks to collect anything that might hold signs of life.
| The latest from the Mars Society conference |
| NASA scientists criticized their employer Friday at the Mars Society'sconference in Toronto, with one saying that the cost model that has kept a continuous human presence at Antartica could pay for missions to put humans on Mars. |
Another cost-cutting approach involves relying on the Russians. Click here to read more . |
It dumps that material into a chamber and then begins to search the material for molecular DNA the most basic building block common to all known life.
Building an instrument that can travel to Mars to directly search for traces of DNA is the dream of researchers at the Stanford Genome Technology Center. The dream is actually within reach, according to Viktor Stolc, one of those researchers, who is working with NASA in the early stages of building just such a machine.
That dream, and the promise of other basic genetic research took Stolc to the Canadian High Arctic this summer to participate in NASAs Haughton-Mars Project field season. The project is a NASA-sponsored effort to study the geology and biology of the islands
Haughton impact crater in order to learn how future planetary missions might be done.
A green oasis inside Haughton Crater is fertile ground for biologists studying how organisms can adapt to harsh, extreme environments.
"We are building an instrument at the Stanford Genome Technology Center which is capable of detecting single molecules of DNA, one at a time. What we hope to do is couple it with an extracting type of device which will sample rocks on the surface of Mars as part of a NASA mission to look for the presence of DNA."
The extreme stability of DNA, and the fact that it is a sure sign of a living organism makes it an ideal test for the presence of life, Stolc said. Ancient DNA from plants and animals that lived on Earth hundreds of millions of years ago has been found preserved in amber.
"Even if life is no longer present on Mars in active form, its possible that DNA may have been preserved and we may be able to detect it single molecule at a time," he said.
Viktor Stolc with culture samples of Arctic bacteria
For several weeks in July and early August, Stolc worked out of a field laboratory set up in a 10- by 12-foot (3- by 3.6-meter) canvas tent on the islands rocky terrain. Sharing the tents precious table space with geologists and their ever-growing collection of rock specimens from the crater, he incubated and cultured bacteria, growing it so he can eventually sequence the DNA of the craters microorganisms. Cluttered by necessity, and filled with dust from the dry polar desert, Stolcs lab was by no means primitive: it still had the most basic equipment, powered by a diesel generator, that any modern geneticist needs.
Sweeping up the genetic blueprint of an ecosystem
If building a device to find Martian DNA doesnt sound ambitious enough, Stolc is also busy with a project that seeks to sequence the entire genome of not a single species, but the entire ecosystem of the area around Haughton crater. The genetics community only recently finished sequencing the human genome. That is, mapping the exact location of every element in human DNA.
Various other genetics projects have also managed to map the genomes of relatively simple life forms such as like yeasts, and nematodes.
~
But to gather together material from a whole mess of living things -- including hundreds of microorganisms -- and untangle the genetic code of each organism from that mixed biological stew is unprecedented. Stolc went to Devon Island to attempt to do just that. He took advantage of the never-setting sun and a relatively simple ecosystem to collect biological samples from rocky slopes, small lakes and trickles of water that pass for streams.
He dug up plants, scraped lichens from rocks, and carefully peeled algae mats from the mud around small "lakes" bodies of water that would be fortunate to be called ponds anywhere else in the world. But for this harsh polar desert, mere survival seems a miracle.
Lying down in the center of a muddy patch of ground covering plants in Haughton Crater last week, Stolc took a handful of digital photos. "My colleagues back at Stanford might not believe all the diversity that actually exists here," he said as he snapped a string of images of the scraggly grasses and blossoms that stood up like dandelions. "Its a very dry, desert-like environment," that has cycles of continuous sunlight in the summer, and complete darkness for months at a time during the winter, he said.
"What were doing here is looking at the genetic information in these organisms that live here in the Arctic in the extreme environment to try to understand what types of gene sequences enable organisms to thrive in extreme environments," Stolc said. "We hope to find links in the DNA sequence that are specifically adapted for this location." Specific adaptations might include ones that help organisms withstand extreme cold, or exposure to high doses of ultraviolet light, or get through long spells of dehydration.
Stolc is not alone in his fascination with such organisms. In fact, interest has grown as scientists have found more examples of life thriving under conditions once thought unlivable -- so much that these organisms now have their own designation: Theyre called extremophiles.
Other biologists at the Haughton-Mars Project are also studying these critters.
Earths superbug examined
Deinococcus: Could it have a future on Mars?
One of the toughest bugs on Earth might be called an
extremophile, even though it usually lives under very normal conditions. It is the tenacious Deinococcus radiodurans; a bacterium that can withstand some of the harshest doses of radiation humans can dish out. Its was discovered during the 1950s when tinned meat that had been supposedly sterilized with of gamma radiation spoiled. The meat was found to be teeming with Deinococcus radiodurans, which has a unique ability to quickly repair any genetic damage caused by radiation. This ability earned the microorganism its name, which translates as "strange berry that withstands radiation."This toughness has implications for current Mars missions as well as the future search for life on other planets, said Alessandro Airo, a biochemistry graduate from the Free University of Berlin who is now interning at NASAs Ames Research Center. Airo specializes in Deinococcus radiodurans, and is searching the environs of Haughton crater to see if there are any strains of this organism that live in the High Arctic.
Planetary protection experts in the worlds space agencies are keen to find a way to kill Deinococcus on spacecraft, because using radiation, a common method of sterilizing spacecraft, is ineffective against this microorganism, so any research into the microorganism helps.
The so-called superbug has been found throughout the world, including in Antarctic granite, but it is most comfortable at temperatures of 95 to 100 degrees Fahrenheit (35 to 38 degrees Celsius). A strain of D. radiodurans that is active at the much colder temperatures of Devon Islands polar desert would be a tough bug indeed, Airo said.
He is trying to find such a strain. Airo has come to the Devon Island to join the Haughton-Mars Project in order to take biological samples from streams, small lakes and dry rocks, hoping to find a thriving strain of the strange, radiation-resistant berry. Such a strain might very well possess the same coping mechanisms that any sort of existing life on Mars would have, Airo said.
"Were using Deinococcus radiodurans as a model organism for present Martian life," he said.
While both Airo and Stolc are using their research in order to understand what life on Mars might be like, and how to better search for it, they also see a use for their work even if Mars has never yielded a single living cell.
"You can imagine that if we had a catalog of gene variants for all the genes that are found in a microorganism that enable microorganisms to withstand dryness and cold. It might be possible one day to engineer microorganisms to contain those sequences such that potentially they could be used for terraforming Mars," Stolc said.
Whether such capability would lead to the greening -- or "Frankensteining" -- of Mars might be an ethical debate for a future decade, but the technology to make a superbug for Mars that might then begin to produce oxygen on the planet could be a reality of the foreseeable future, Stolc said.
Coming tomorrow: We Have the Technology
advertisement
