posted
So later today Nasa will be announcing... something. Right now the official information can be found here. The logline point is:
quote:WASHINGTON -- NASA will hold a news conference at 2 p.m. EST on Thursday, Dec. 2, to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life. Astrobiology is the study of the origin, evolution, distribution and future of life in the universe.
Editing out the rest of this because it made it look more exciting than it really was.
[ December 02, 2010, 05:01 PM: Message edited by: Raymond Arnold ]
Posts: 4136 | Registered: Aug 2008
| IP: Logged |
posted
Wow, that would be huge. I will be picking mmy daughter up from school at that time, but something that huge should be replayed later.
Posts: 2223 | Registered: Mar 2008
| IP: Logged |
quote:Originally posted by Blayne Bradley: Didnt we already find silicon based life in Russia?
After a quick google search, it seems the answer is no. Silicon life has been discussed hypothetically a lot but not actually found.
Posts: 4136 | Registered: Aug 2008
| IP: Logged |
posted
That's much more exiting that what I was expecting. I was anticipating some new amino acid, or something similar, found on an asteroid or space rock.
A fundamentally different type of life is much, much more exiting.
Posts: 1711 | Registered: Jun 2004
| IP: Logged |
posted
I'm curious if this evolved from life as we know it, crashed here in a meteor, or was an example of something left over from the early Earth.
Posts: 3134 | Registered: Mar 2005
| IP: Logged |
quote:Originally posted by Blayne Bradley: Didnt we already find silicon based life in Russia?
Only in their models.
Their models are implanted with semiconductors / computer chips? They can make you better, stronger, faster.
Posts: 688 | Registered: Nov 2008
| IP: Logged |
The bacteria still have phosphorous, but if you give them a super high diet of arsenic, they use it in their DNA. So, lab based, not found in nature. It is a nice proof of concept though.
Posts: 2223 | Registered: Mar 2008
| IP: Logged |
posted
Either I haven't gotten to the bad part, or I just didn't understand it yet, but, why is this not as important as the headline states?
Posts: 21898 | Registered: Nov 2004
| IP: Logged |
posted
Well, it seems we're dealing with a microbe that has evolved to be able to substitute arsenic for phosophorus and still survive. The hype leading up to this was implying that they had discovered an arsenic based life form. That made me think that had found a life form that had evolved along a completely different path, based on some sort of drastically different DNA structure. From the above article, what was quoted in the OP is completely misleading:
quote:At their conference today, NASA scientist Felisa Wolfe Simon will announce that they have found a bacteria whose DNA is completely alien to what we know today. Instead of using phosphorus, the bacteria uses arsenic. All life on Earth is made of six components: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. Every being, from the smallest amoeba to the largest whale, share the same life stream. Our DNA blocks are all the same.
But not this one. This one is completely different. Discovered in the poisonous Mono Lake, California, this bacteria is made of arsenic, something that was thought to be completely impossible. While she and other scientists theorized that this could be possible, this is the first discovery. The implications of this discovery are enormous to our understanding of life itself and the possibility of finding beings in other planets that don't have to be like planet Earth.
emphasis mine. granted, there is a line stating that it uses arsenic instead of phosphorus, but I think the general gist of the article, and others that came out before the press conference were very misleading. Though, this is nothing new in the media, especially when dealing with scientific discoveries.
Posts: 8741 | Registered: Apr 2001
| IP: Logged |
posted
I think the "underwhelmed" factor is going to happen whenever Nasa makes any kind of pre-announcement like that. It's not physically possible for Nasa to say "new discovery related to search for extra-terrestrial life" without it getting overhyped to some degree.
In the internet age, if you don't want people to get disappointed by stuff like this, you need to do the whole announcement at once, methinks.
Posts: 4136 | Registered: Aug 2008
| IP: Logged |
posted
I don't get the misleading part. The OP describes a new arsenic based backbone. We got a new arsenic based backbone, eh?
Posts: 7593 | Registered: Sep 2006
| IP: Logged |
posted
I'm only going off the OP here, but it doesn't say anything about evolution (well, except as part of a definition of astrobiology).
Posts: 7593 | Registered: Sep 2006
| IP: Logged |
posted
How else would a completely different kind of life whose DNA was completely alien to us come about if not through evolution? (Intelligent Designers need not apply)
Posts: 8741 | Registered: Apr 2001
| IP: Logged |
posted
Let me elaborate, the OP says that the DNA is completely alien to what we know today, it doesn't say a word about it evolving, independently or not.
Posts: 7593 | Registered: Sep 2006
| IP: Logged |
posted
True, but I would argue that to say that DNA which is able to substitute one element for another is completely alien is a significant overstatement of the situation already. My further extrapolations (about different evolutionary paths) seem like relatively obvious implications from the initial misleading statements. It seems i'm not alone here at Hatrack or elsewhere.
posted
Anyways AFAIK, it is completely alien to what we knew about yesterday. The closest I think we've ever gotten are new amino acids in proteins (rather than DNA) that we didn't know about.
Edit to add: Surely, a new evolutionary path would be way more huge and I probably wouldn't have lead with "New backbone, whoa" Posts: 7593 | Registered: Sep 2006
| IP: Logged |
I think you and I just have different definitions of alien. I think foreign, unexpected, previously unknown, all work in that situation. Completely alien to me implies something much more significantly different!
just scrolled up and saw your initial post. Posts: 8741 | Registered: Apr 2001
| IP: Logged |
posted
Very exciting. I anxious to hear more. For example, I'd like to know if these are otherwise similar to normal bacteria. Do they use the same genetic code. Do they have highly conserved enzymes, like cytochrome C? These questions would be key in answering whether this represents an independent route of abiogenesis, or these bacteria "evolved" from phosphate based bacteria. I'm think the latter is much more likely.
I was also intrigued by the fact that Mono lakes novel chemistry is very recent. That is it's only been isolated from its fresh water intake for 50 years. The idea that this dramatic an adaptation could occur in only 50 years is mind blowing.
Posts: 12591 | Registered: Jan 2000
| IP: Logged |
posted
Rabbit: these were lab-created from phosphate-based bacteria, not found in the wild. They took phosphate bacteria living in an arsenic-heavy environment, then exposed them to huge quantities of arsenic.
Posts: 15770 | Registered: Dec 2001
| IP: Logged |
posted
Yes, fugu, I know these bacteria were grown in a laboratory where they were exposed to a phosphate free, arsenic rich environment. It is, however, incorrect to presume that these were "phosphate bacteria" when there were found in the wild. There would have been no way to determine that. The most that can be said, is that when grown in the laboratory, these bacterial were able to use phosphate and arsenic somewhat interchangeably. It is highly unlikely that this characteristic evolved in the laboratory rather than in Mono lake.
Posts: 12591 | Registered: Jan 2000
| IP: Logged |
posted
Perhaps I should have been more clear. This isn't a new bacterial discovery. They took a 'normal' bacteria (for being an extremophile) in a high arsenic environment and did this; there's nothing particularly unusual about the bacteria otherwise (again, for being an extremophile). It isn't even Archaea.
Posts: 15770 | Registered: Dec 2001
| IP: Logged |
quote:Originally posted by fugu13: Perhaps I should have been more clear. This isn't a new bacterial discovery. They took a 'normal' bacteria (for being an extremophile) in a high arsenic environment and did this; there's nothing particularly unusual about the bacteria otherwise (again, for being an extremophile). It isn't even Archaea.
Where did you get this information. It certainly isn't clear from the NASA press release whether they have done enough molecular level characterization of this bacteria to determine what is and is and is not unusually about it. They call it a gammaproteobateria, but it would not be at all unusual for classification of this nature to be changed dramatically when more detail is learned about he bacteria.
All I was saying is that I would like to hear more detailed information on the biochemistry of the organism. If you have a link to more detailed information on this discovery, please share.
Posts: 12591 | Registered: Jan 2000
| IP: Logged |
posted
There's a heck of a lot more information available than the NASA press release. I suggest you start with the Science journal article. The bacteria was easily classified by gene sequence comparison and, along with extremely close relations, has been studied quite thoroughly. It exhibits strange characteristics, but only when subsisting on arsenic (which thus are likely not strange for a bacteria subsisting on arsenic, though that could easily change as we find more examples, assuming this all turns out to be replicable).
Posts: 15770 | Registered: Dec 2001
| IP: Logged |
posted
My apologies for thinking you were familiar with one of the premier scientific journals in existence.
Posts: 15770 | Registered: Dec 2001
| IP: Logged |
posted
She might have thought you meant a science journal, vs Science journal. Or she might have just been being lazy and letting you find the exact link. Posts: 2223 | Registered: Mar 2008
| IP: Logged |
quote:This arsenic-metabolizing bacterium, SLAS-1, was found in Searles Lake, California. Located in the Mojave Desert, Searles Lake is about ten times saltier and about 70-times more alkaline than seawater and contains arsenic in concentrations that are unusually high (about 4 mM). The bacteria isolated by the USGS scientists were found to not only tolerate the extreme conditions, but to derive energy from metabolizing arsenic.
posted
That's a related discovery (and very interesting in its own right), but not the same discovery. They found that the bacteria in question has a bio-oxidation cycle using arsenic (very unusual), and that this was actually an important part of the bacteria's life cycle in its native environment (at that time a unique discovery).
This discovery is about the organism not just metabolizing arsenic, but using arsenic as part of its internal building blocks, which still function.
Posts: 15770 | Registered: Dec 2001
| IP: Logged |
quote:Originally posted by scholarette: She might have thought you meant a science journal, vs Science journal. Or she might have just been being lazy and letting you find the exact link.
Or I might have simply been asking the information commonly included in a reference, like date, volume, authors that might make is easier for a person living in a developing country to actually get the correct article.
Posts: 12591 | Registered: Jan 2000
| IP: Logged |
Topic Closed
Printer-friendly view of this topic
![[Wink]](wink.gif)
![[Smile]](smile.gif)
![[ROFL]](graemlins/rofl.gif)
![[Roll Eyes]](rolleyes.gif)
