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RE: exobiology possibilities

On the contrary: we have every reason to think that all life on Earth studied 
so far are descendants of a single instance of life, and every reason to 
dismiss the possibility that any known terrestrial life is of independent 
origin. A good reason for this is the fact that A, T, C & G are NOT the only 
possible nucleotides.  Furthermore people have synthesized nucleic acid 
analogues in the lab that work essentially like DNA and RNA but which have 
different backbones. The fact that all living things use only the one system 
when there are numerous alternatives which are seemingly just as likely points 
to a common origin. Statistically, we would expect alien life will  like have 
DNA/RNA analogues using other nucleotides and/or backbones, if indeed they used 
these forms of molecules as the carrier of genetic information.

The Lost City microbes fall within the family tree of other life, and use the 
same genetic carriers in the same fashion the rest of Earth life does.

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
Fax: 301-314-9661               

Faculty Director, Science & Global Change Program, College Park Scholars
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA
> -----Original Message-----
> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf Of 
> Ruben Safir
> Sent: Thursday, March 12, 2015 4:17 AM
> To: dinosaur@usc.edu
> Subject: exobiology possibilities
> http://finance.yahoo.com/news/discovery-one-saturns-moons-just-182029759.html
> This article is worth reading only because it point to the possibility of an 
> independent evolution of life, which brings up a question I
> have long had.
> We really don't know if all life on this planet comes from a single 
> continuous linage.  The organism that exist in the lost city might not
> be related to anything on the planet.  And similarly, is possible that 
> flowering plants, as an example, some from several branches of
> plant life, in a form of convergence where closely related specifies 
> simultaneously develop like features, even controlled by similar
> haplans and control genes?
> Why should the course of evolution be simple?
> Ruben