jump to navigation

Artificial DNA Created April 20, 2012

Posted by Metabiological in Beyond Earth, Genetics.
Tags: , , ,
add a comment

In what appears to be a first scientists have created the first synthetic genetic material that can store information and evolve in a similar way to DNA.

Researchers at the MRC Laboratory of Molecular Biology, in Cambridge, developed chemical procedures to turn DNA and RNA, the molecular blueprints for all known life, into six alternative genetic polymers called XNAs.

The process swaps the deoxyribose and ribose (the “d” and “r” in DNA and RNA) for other molecules. It was found the XNAs could form a double helix with DNA and were more stable than natural genetic material.

Cool news by anyone’s standard.

I will however take issue with one things stated by the authors.

“There is nothing Goldilocks about DNA and RNA,” Holliger told Science. “There is no overwhelming functional imperative for genetic systems or biology to be based on these two nucleic acids.”

That is overstepping bounds to me.   While this has certainly proved the possibility of other molecules forming the basis of genetic material it says nothing about the probability of said molecules actually forming on their own.  As of right now the only truly concrete thing we can say is that despite a very long time to try out different options the only type of genetic material to evolve are DNA and RNA.  Their prevalence, and the lack of any competitors, are the only evidence we have for how successful different types of genetic material are.  DNA may no longer be the only possible configuration but it still may be the most likely one and therefore the most likely basis for life on other worlds.    Far more work needs to be done in order to knock DNA off it’s pedestal.

Advertisements

Billions Of Life Bearing Planets? March 30, 2012

Posted by Metabiological in Beyond Earth.
Tags: , , , ,
add a comment

Could the universe be saturated with life?  Is our galaxy filled with literally billions of worlds harboring that most precious of gifts, that strange and wonderful collection of matter and processes we call life?  According to a new study by astronomers that may very well be the case.

A new result from ESO’s HARPS planet finder shows that rocky planets not much bigger than Earth are very common in the habitable zones around faint red stars. The international team estimates that there are tens of billions of such planets in the Milky Way galaxy alone, and probably about one hundred in the Sun’s immediate neighbourhood. This is the first direct measurement of the frequency of super-Earths around red dwarfs, which account for 80% of the stars in the Milky Way.

“Our new observations with HARPS mean that about 40% of all red dwarf stars have a super-Earth orbiting in the habitable zone where liquid water can exist on the surface of the planet,” says Xavier Bonfils (IPAG, Observatoire des Sciences de l’Univers de Grenoble, France), the leader of the team. “Because red dwarfs are so common — there are about 160 billion of them in the Milky Way — this leads us to the astonishing result that there are tens of billions of these planets in our galaxy alone.”

While this doesn’t prove anything conclusively it’s still very interesting for a few reasons.  One, the novel approach of looking in a historically undervalued area (Red dwarf stars).  Considering the sheer number of them that we apparently knew were out there it’s somewhat surprising it took someone this long to actually estimate the number of planets around them.  Second is how conditions around Red Dwarfs differ from those we are used to around stars like are own.  According to the researchers in addition to the obvious difference of being smaller and dimmer (thus allowing the Goldilocks zone to be closer to the planet) Red Dwarfs appear to lack large Jupiter sized worlds and are subject to stellar eruptions.  Jupiter worlds may be important for protecting smaller rocky planets from life-destroying comets and meteors while solar flares are known to release potentially deadly radiation.  Both of these factors could make the researcher’s estimates of life too generous.

But whatever.  Putting practical considerations aside if true this is amazing news.  The idea of a universe filled with life, variegated in all the forms evolution can dream up but connected by virtue of our shared status as reflections of Life itself, is the kind of idea that got me into the sciences in the first place.  The kind of idea that fills me with a wonder and amazement at the unfathomable beauty of the cosmos.  Sorry for waxing poetic there for a moment.  I hope you’ll forgive a young man his optimism and bright-eyed enthusiasm.

P.S. Nobody mention the Fermi Paradox.  I’m in too good a mood to worry about the Fermi Paradox.

NASA Scientist Claims To Have Found Alien Life March 5, 2011

Posted by Metabiological in Beyond Earth.
Tags: , , ,
add a comment

Having already got my hopes up once this year about the possibility of extraterrestrial life only to be brought down by an admittedly cool new life form I’m now very skeptical of any news of this sort coming from anyone involved with NASA.

Short version: a scientist working for NASA has claimed to have discovered fossil evidence of alien life within meteorites.  When I first heard this I immediately had flashbacks, as I’m sure most of you did, to an eerily similar incident over a decade ago regarding life found in martian rocks.  You may remember that the President Clinton actually addressed the nation on the discovery (which has since been largely debunked.)

I’m sure many people will make a big deal of the fact that some of the supposed fossils resemble primitive earth life such as cyanobacteria.  I can almost hear the cries of “how do you know it didn’t just come from earth?”  While not an outright stupid question I don’t think its a deal breaker either.  Cyanobacteria are a very primitive and ancient life form and it would stand to reason that primitive alien life would take a largely similar form (assuming of course similar biochemistry).  In addition some of the other fossils appear to be nothing like anything seen on earth.

In the end something about this just doesn’t smell right for it to be an actual discovery.  Why is this being published in an online journal rather than say Science?  Why isn’t NASA making a much bigger deal about this than it is?  Why did I first hear about this through a ticker story on the Yahoo website?  Maybe I’m just jaded due to the aforementioned let down but I really don’t expect this to turn out to be anything.  Still, one can hope.